Thriller

is the seventh episode of the tenth season and the 203rd overall episode of Grey's Anatomy.
==Short Summary==
It's Halloween and the doctors of Grey Sloan Memorial are hit with a barrage of spooky patients, which affects their own plans and puts one doctor’s well-being in jeopardy. Meanwhile, Derek collaborates with Ben on a new surgical technique and Richard angers Bailey when he asks a second year resident to perform his next surgery.
==Full Summary==
Leah wakes up next to Arizona in the hotel room. She gets ready to leave, but Arizona asks if she wants breakfast. Leah says she knows she's not supposed to sleep over and apologizes, but Arizona says it's okay. Leah thinks it's not, as she's all about easy, and she leaves to find a costume for Jo's party tonight. Arizona then remembers it's Halloween. She tries to wish Leah a Happy Halloween, but Leah leaves.
An extremely busy Meredith meets Derek in the hallways of the hospital. She hands him over the wings of Zola's butterfly costume and asks him to take care of the rip in the wings. She now has to order a 3D printer for her research, for which the grant was approved. He tells her a little about his brain mapping project and after asking if the party tonight is still on, he leaves her. Meredith asks Alex if he got the house ready for the party, and he says he did. However, he only got the keg and forgot about the rest. Cristina overheard them talking and asks them if they're having a party. Meredith says they'll trick-or-treat from Alex's house after the Halloween party with families from the daycare, because they don't have neighbors around their own place to trick-or-treat. Cristina didn't know about this, and Meredith says she should come. Cristina doesn't seem enthusiastic about the idea, and Meredith says she probably doesn't want to be around kids hopped up on sugar. "Right, cause I hate children," Cristina says, after which she says that she does love Meredith's kids. Meredith then apologizes for not having invited her, and then invites her to come and have a drink.
Jackson and Stephanie, who's wearing special glasses, enter the hall, where Jo and Leah ask her if she doesn't have any side effects from her eye surgery, as Leah's uncle still has pain from the same surgery he had 3 years ago. Jackson makes a comment about Stephanie coming back to work too early while she should stay at home for 2 days. "I'm a second year resident, 16 hours of recovery is already more than I can afford," Stephanie says. 
She and Jo enter the small room with computers, where Jo informs her that Alex still hasn't talked to her, making her think their relationship is over. Stephanie doesn't believe this, and says it's time to go round on Webber. As she wants to walk outside, she walks into the wall. "Are you sure you don't want to go home?" Jackson asks. 
At a nurses station, Callie asks April and Owen if they have Halloween plans. April says she'll go to Matthew's thing as a Velveteen bunny, and Callie comments that the costume still needs work. She asks Owen about him and Emma, and Owen says they're no longer a thing, as Emma thought he wasn't ready yet because he never mentioned being married before. Emma told him to call her when she's ready, and as Callie and April start discussing whether or not he's ready, Owen walks away. They then agree he's not ready. April leaves, when Arizona comes over to ask Callie what time they want to meet for Sofia's costume, which she has in her car. It turns out they both have different costumes for Sofia, a princess costume and an astronaut costume, as she told her mothers different things she wanted to dress up as. Arizona proposes to let Sofia decide between the costumes, but Callie says Arizona can take Sofia.
Bailey enters Richard's room, where Stephanie tells her that Richard will allow one of the interns to perform his surgery. "Not you, no offense, but I heard you walked into a wall this morning," Richard says. Bailey asks why she can't do the surgery, and thinks the interns are not ready, contrary to Richard. He asks them to explain how they'd do the surgery, and suddenly Ben Warren answers his questions from the doorway. Bailey hugs him, and he tells her he came early because he didn't want to miss trick-or-treat. Ben asks which intern he's going to pick, and Richard tells Bailey to observe them in the ER so she can tell him which one deserves it. She starts to object, but Richard has made his decision, so Ben pulls her out of the room.
Outside the room, Bailey is not planning on doing anything special. She disinfects her hands while she says the residents are going to kill the most important patient she's ever had. Ben wants Halloween to be their family's thing, as it was his family's thing, so he proposes to take care of it. Bailey smilingly reminds him that it's a holiday for children.
The paramedics bring in Victor, who was attacked and bitten by another man, like some sort of zombie. Next, the zombie man is brought in. He has two bullet holes over his heart, yet he is stable. The extremely wild man is handcuffed to the gurney and trying to break free. The man calms down, and Leah tries to listen to his heartbeat. Suddenly, the man opens his eyes again, grabs Leah and bites her neck. She screams in pain.
Jo and Stephanie are cleaning out the bite wound, but Leah wants them to patch her up quickly so she won't miss out on Richard's surgery. "Yes you are," Bailey says, who makes them jump up as she appeared out of nowhere. She tells her she isn't going into an OR with an open wound, and that she has to run an infectious panel, including rapid HIV. Meanwhile, Stephanie removes a tooth from Leah's skin. "One down," Bailey says.
Cristina meets Owen in the trauma room with the zombie man. He wants her to say trick or treat, but she refuses. She does it anyway when he tells her she's no fun sometimes. He then shows her the scans of zombie man, which indicate he has situs inversus, which means all his organs are mirrored to the normal position. This is why he was fine after being shot, and why Leah couldn't find the heartbeat. Cristina says she has wanted to see this since med school, and he wishes her a happy Halloween.
A businessman is in the ER with his daughter. He tells Jo that he had Halloween early with his daughter, who's very excited about the holiday and dressed up as a witch, as he has a business trip. Normally, she can come with him, but not this time. Alex comes over, and he examines Taryn, the daughter. The father explains that she got a stomach ache while eating candy and watching a movie. Alex snaps at the father, whose phone keeps vibrating, and examines the kid. He concludes it's probably not the candy and demands labs. Taryn asks if she can still go trick-or-treating, and Jo says that the best trick-or-treating of Seattle is on the peds floor of the hospital. 
Victor is being treated by April and Jackson. He can't get over the fact that the zombie didn't die when they shot him. Jackson is treating the bite wound on Victor's face. He has pain and thinks he's becoming a zombie now as he was bitten, but April says zombies aren't real. Victor then has a stroke, and April feels a mass near the carotid artery. Jackson books an OR.
Stephanie still has trouble seeing and misreads a patient's name. The lady wants to go home, and her son Philip says that she's afraid of hospitals. She hurt her leg, and he had to drag her to the hospital to have it checked out. While Stephanie is taking off the bandage, Marge continues asking to take her home. As she takes off the bandages, a fly flies out of it. Marge then says it happened about four months ago, and when Stephanie lifts the last bandage, she sees maggots crawling in the open wound.
Stephanie tells Meredith and Callie what she saw. She mentions her eye surgery, which causes Meredith and Callie to have her go buy candy for Meredith's party. They then go see Marge.
In the research lab where Derek is working on his research for thought control prosthetics, Ben is looking for a mirror head lamp that doctors used to wear, as he wants to find the perfect costume for Tuck, who wants to dress up like a mad scientist. Derek says they stopped using those centuries ago and asks him what they're teaching him in LA. Derek himself is trying to figure out how to insert the sensors in the skull. Ben then sees how poorly Derek fixed Zola's butterfly wings. and says he can do it better. "What are you teaching up here?" Ben asks.
While Callie and Meredith explain how they'll treat Marge's infected wound (including a surgery), Marge starts panicking more and more. When Callie mentions sedatives, Marge yells "no needles!", drawing everyone's attention. Meredith closes the curtains, and Philip explains to them that his mother's fear of doctors got worse when his dad died. He asks about the sedatives, but Meredith then says she has an idea. She says she'll be back, and goes to the gift shop.
Shane is doing a quick exam of the patients in the waiting room. The last patient is an old, weird, scary lady, who says she's waiting for her doctor, Heather Brooks. Shane says Dr. Brooks is not here, but the lady says she always is. 
In the ER, Shane tells Bailey the lady only wants Heather, and asks if he should tell what happened. Dr. Bailey doesn't think telling this woman that her favorite doctor died is a good idea. When they see an empty waiting room, Shane says the lady was there a second ago. "Murphy was bitten, Edwards is blind and you're bonkers. Another one down," Bailey says and she walks off. Shane stays behind and when he turns around, the lady stands in front of him. He wants to know her name so he can start treating her, but she wants to wait for Heather.
Owen and Cristina are operating on the zombie man, and they're confused by the situs inversus. He asks about her plans tonight, and she tells him about Meredith's party. She's not sure Meredith wants her to come, or if she just felt like she had to invite her. "It's so complicated," Owen says, and Cristina says it is, as she and Meredith used to know what the other one was thinking. The patient starts deteriorating, and they concentrate on the operation.
Meredith gives Marge an eyeshade, so she doesn't have to see anything and not have to close her eyes so tight like she's doing now. Marge puts it on, and to calm her, she and Meredith start talking about her Halloween traditions. Callie comes over, and they take her to get a gown.
Jo comes to Alex with Taryn's lab results, and she says the father would like to know if he has to change his flight. Alex snappingly says he should, as the girl might be surgical. Jo asks him what his problem is, and says that Taryn's father is not his father and not an ass. She asks him to tell her what she can do to make the situation with his father better for him, but he doesn't answer.
Marge and Meredith enter the OR, while still talking about Halloween. Meredith assures her she'll be there the whole time, and Marge then says she's ready. 
Ben and Derek are suturing the wings while talking about Halloween. Ben proposes something to make the wings fan out, which seems to spark something in Derek's head.
In Richard's room, Bailey is ranting about how incompetent the residents are. Richard then says that she is the problem, not them, as he is trying to teach them while she won't let them learn. As he's unsure that he will ever operate again, teaching the residents is the only thing he has that keeps him going. She is standing in the way of that, which is why he'll have somebody else supervise them. He fires her from his case, and tells her to walk out. She rightens her lab coat, and leaves.
In surgery, Callie discovers there's almost no necrotic tissue, meaning the maggots may have saved Marge's life. Meredith mentions the trick-or-treating, and Callie says she's not coming because she doesn't want her bickering with Arizona to ruin Halloween for Sofia. Meredith mentions what they'll do at the party and promises to take pictures for Callie, when a nurse tells her that Richard wants to know if she has room on her schedule for a cystogastrostomy. "Maybe Derek can take pictures?" Callie jokes.
While eating candy, texting and relaxing in the resident's lounge, Leah and Stephanie talk about Leah potentially having HIV and Stephanie's eye sight. They agree they're both screwed.
Jackson and April are operating on Victor, and Jackson gets the - according to April - 50th misspelled text from Stephanie. Jackson asks the nurse to text back that she has to keep using her eye drops, and that she is beautiful. April remarks that he was never that nice to her when she would spin up, and he replies he's trying to be a better boyfriend now. She says his behavior helped her get her act together. "I'm getting married, and I'm saving this guy's life and his face" she says. "And that's all because of me," Jackson jokes.
Owen is still having difficulties in surgery, but Cristina says he's overcomplicating it. She tells him to tell his right hand to do what his left hand usually does, and vice versa.
Meredith tells Richard she doesn't have the time. He apologizes for having said that she should've let him die and for ever having felt like that. "I would've never gotten here if it hadn't been for you, so I'm sorry," he says, and begs her to help him teach the residents. 
Derek shows Ben his plan to use fan sensors, so they can go in through a small hole in the skull and open up underneath it. Ben notices he doesn't seem to regret having stepped back from surgery, and Derek confirms. 
Alex is rushing to the ER, and he shows Jo Taryn's labs, which show that Taryn's body is not producing enough adrenaline. Jo then starts thinking about what can cause this and then says that his dad mentioned he took her with him on a business trip to Brazil. Alex asks why she didn't put that in the chart, and they run to the ER.
There, they find her bed empty. The dad comes back after having finished his call to cancel the flight. Alex asks where she is, but he doesn't know. Before he went away to make the call, she was asking about trick-or-treating around the hospital. He asks what's going on. They explain that adrenaline keeps your organs from going into shock when you get hurt or scared, and because she isn't producing enough adrenaline, she could go into shock when something scares her. That can happen easily, as it's Halloween. The father only understands his daughter might get scared to death, and Alex and Jo run off to find her.
Shane is trying to find his patient, but she disappeared again. He asks Stephanie if she's seen her, and mentions there is no record of her anywhere and that she was Heather's patient. Stephanie says she was probably unhoused and uninsured, as Heather used to take those people in.
As Alex is looking for her, Taryn is walking through an empty, dark hallway, trick-or-treating. A patient brushes her off when she appears in his doorway. Suddenly, Shane's ghost lady patient comes hobbling through the door and tries to walk towards Taryn, who falls down. 
Alex finds them, and he yells for a crash cart and gurney. While nurses take care of Taryn, Alex checks on the lady. He diagnoses her, goes back to Taryn and instructs the nurses to have the ghost lady taken to the ER. 
Callie has helped to make Marge's room feel more like home, with having taken out all the unnecessary medical equipment and decorations. She asks Marge if she wants her to stay, but Marge asks if she doesn't have kids. Callie says she does, and Marge says she has to enjoy Halloween with her kids before they get to 10 and go off with their friends, getting into trouble. "You gotta enjoy it while you can," she tells Callie.
In the scrub room, Cristina tells Owen she'll go to Meredith's party to talk with Meredith and move past this whole thing. Owen says that's good when Cristina gets a text from Meredith. "If you're coming to the party, could you bring cupcakes? If not, no problem," Cristina reads out loud. "What does that mean? It's no problem if I don't go, or no problem if I don't bring cupcakes? And if I don't go, there's no cupcakes, or will someone else bring them? And if someone else is bringing them, why is she even asking me?" Cristina asks, and Owen then advises her not to overcomplicate it, and just go to the party.
In the PICU, Jo tells Taryn's dad that there won't be another adrenal crisis, so Taryn should make a full recovery. The dad is doubting himself and beating himself up, and Jo advises him not to let what Alex said get to him. She says he's great with kids but so crappy with other people. "He knows you're a good dad," Jo assures him.
Jackson and April tell Victor they haven't fixed his face yet, only the damage to his carotid artery. Victor starts panicking about the zombie again, thinking he's put in quarantine. Jackson tries to get through to him, but he keeps on going until April yells at him and claps her hands, and gives him a perfectly logical explanation for what happened. "See, someone starts spinning out, you just shut it down. But, you know, you can still tell him he's pretty," April jokes to Jackson after taking him apart.
In the ER, Derek tells Meredith that he fixed the wings and figured out the sensor array. Meredith says she has to find a resident to perform the surgery on Richard, and thereby won't make it home in time to trick-or-treat. Derek walks away and says he'll meet her at the house. Meredith then walks up to Shane, who's finally treating the ghost lady, and tells him he can perform the surgery. He rejects the offer, as he wants to stay with the lady. Jo comes over and asks Meredith to talk about Alex. "I know a place we can go where no one will interrupt us," Meredith says. 
In the streets, kids are trick-or-treating. Bailey comes home and finds her house beautifully decorated as a laboratory. Ben and Tuck are dressed up as a zombie and a mad scientist. Tuck is excited, and Bailey tells him to get his trick-or-treat bag. "I told you this is my holiday," he says, and she says he's amazing as they kiss. Ben says he wants to do more things like this with his family, but Bailey says he can't just drop out of residency in the middle. "I did. I quit," Ben then says. This surprises Bailey.
Arizona asks a crying Leah if she's seen Jo, but asks her what's going on when she notices Leah is crying. Leah pretends she's fine but then says that she got bit and is waiting for the HIV test results. Arizona asks why she didn't tell her, and Leah answers she wanted to be easy peasy. Arizona sits down next to her and tells her about her first disease scare and how scared she was. "Right now, it's not the time to be easy peasy," Arizona says. 
In the ER, the ghost lady's breathing is much better. Shane then tells her Heather died three months ago, and he asks if Heather was treating her under the table. The lady confirms and says she didn't want to get Heather in trouble, which is why she wanted to wait for her. Shane gives her the asthma inhalers Heather used to give her and tells her to come back and ask for him when she runs out of them again. "I'll be your doctor now," Shane says, and she asks if he is as good as she was. "No, but I will be," Shane says. 
Meredith and Jo are operating on Richard. Jo is doing good, and Meredith pushes her to go a little faster. Jo then asks her if she can tell her something about Alex, which he told her not to tell anyone, because he keeps pushing her away and Meredith knows him. Meredith says telling her would be the worst thing to do, as Alex trusted her and told her, so she has to deal with it. "Of course he's going to push you away, because he hates being vulnerable, but that's when he's going to need you to stick with him the most," Meredith says, and Jo says she'll keep trying. Meredith says she has to do better than trying because she is too busy to handle a broken Alex. She assures Jo she can do it.
Bailey and Ben are arguing about him quitting surgery. She wants to have a little consistency, but he says he barely sees her. The doorbell rings, Bailey opens the door, unenthusiastically compliments the kids' costumes and gives them candy. She slams the door and says that he broke up their life previously because entering a surgical residency was so important for him. Ben says he wants to be with her, as the answers the door and enthusiastically gives the kids candy. Bailey says he left town a week after they got married to learn surgery as he loved it, but he says he loves her more than surgery. Bailey turns around, and says she's disappointed in him. Tuck comes in and asks to go trick-or-treating, and Bailey gets ready to leave.
Owen leaves Emma a voice mail message, saying he wasn't ready to talk before because he and Cristina were always so complicated together and that she, on the other hand, is so easy, simple. He realizes this sounds wrong and asks her to delete the message. He hangs up, only to be called seconds later by Emma. 
Meredith and Jo are in Richard's room. Richard asks Meredith to tell him about every detail of the surgery, but Meredith says they should ask Dr. Wilson do that in the interest of education. Richard says he likes the way she thinks, and Meredith steps back to let Jo start talking. Richard wants her to start from the very beginning, and Meredith realizes that's going to take forever. While Jo is talking, she sneaks out of the room and runs off.
Stephanie and Leah are at Joe's bar, dressed up. Leah is happy because her rapid HIV test was negative. She has to go back in 6 months to get tested again, but it's looking good for her. Stephanie is still blind. "Also, no hepatitis," Leah says as she dances her way off. "What are you doing here?" a voice asks, and Stephanie says she's waiting for her boyfriend. She didn't recognize Jackson, making her regret her eye surgery. She realizes coming back to work that early was pretty stupid. Jackson agrees, and he says he planned to take the day off to hang out at home with her, eating chicken soup on the couch while watching movies. "You had to come to work, you had to stress yourself out and strain your eyes, and make yourself miserable, which I told you was gonna happen," Jackson says. Stephanie asks if they can do it tomorrow, but he says they can do it right now and they leave together. 
Meredith enters her old house, where she kisses Derek, who's holding baby Bailey, dressed up as a pumpkin. Arizona tells her the party was great, and Meredith compliments Zola's costume. Callie comes into the room with Sofia, who's dressed up as a Space Princess. Callie tells Meredith that she only has 10 Halloweens with Sofia before she runs off with her friends, and she is not about to cut that number in half. She watches Arizona play with Sofia, and says it's the first thing she and Arizona have agreed on in months. Cristina comes in carrying cupcakes, but everyone is too busy with the kids to notice her. She watches Meredith, puts down the cupcakes and leaves, just as the others get ready to go trick-or-treating. As they leave, Alex has started eating from the cupcakes. Meredith notices this and realizes Cristina has been there. She asks Alex if he's going to stay home to hand out candy, but he says he's going to eat it himself in the dark and pretend he's not home. Meredith doesn't approve of this, and he assures her he'll hand out the candy. 
Cristina enters Joe's bar, where she sits down. The bartender asks her what she's supposed to be, as she's not dressed up. "Sexy," Cristina replies but adds witch as she puts on a hat that's lying on the bar. Shane is sitting on the other end of the bar and asks her if she has nothing else to do tonight. She replies that out of the many options she had, this seems to be the most fun. He moves closer to her and proposes to buy her a drink. He then orders two tequilas.
Alex is watching a movie in the dark while eating candy. The doorbell keeps ringing, and he goes to open it. He sees Jo standing there dressed up as Tinkerbell. "I was wrong about your dad. I made a bad call. I should've let you walk away, but I never would've pushed you towards him if I thought you'd end up hurt. I didn't see it coming. You did and I'm so sorry, but it was one crappy call, that's all," Jo says. He then opens the door and tells her to get in before the trick-or-treaters think he's home. She does so, and he puts off the lights again.
==Cast==
10x07MeredithGrey.png|Meredith Grey
10x07CristinaYang.png|Cristina Yang
10x07AlexKarev.png|Alex Karev
10x07MirandaBailey.png|Miranda Bailey
10x07RichardWebber.png|Richard Webber
10x07CallieTorres.png|Callie Torres
10x07OwenHunt.png|Owen Hunt
10x07ArizonaRobbins.png|Arizona Robbins
10x07AprilKepner.png|April Kepner
10x07JacksonAvery.png|Jackson Avery
10x07JoWilson.png|Jo Wilson
10x07ShaneRoss.png|Shane Ross
10x07StephanieEdwards.png|Stephanie Edwards
10x07LeahMurphy.png|Leah Murphy
10x07DerekShepherd.png|Derek Shepherd
10x07BenWarren.png|Ben Warren
10x07MargeWalker.png|Marge Walker
10x07VictorFabis.png|Victor Brown
10x07GhostLady.png|Ghost Lady
10x07HughDavis.png|Hugh Davis
10x07PhilipWalker.png|Philip Walker
10x07TarynDavis.png|Taryn Davis
10x07WilliamGeorgeBaileyJones.png|Little Tuck
10x07ParamedicGrace.png|Paramedic Grace
10x07Bartender.png|Bartender
10x07Zombie.png|Zombie
10x07Paramedic2.png|Paramedic #2
10x07ORNurse2.png|OR Nurse #2
===Main Cast===
*Ellen Pompeo as Dr. Meredith Grey
*Sandra Oh as Dr. Cristina Yang
*Justin Chambers as Dr. Alex Karev
*Chandra Wilson as Dr. Miranda Bailey
*James Pickens, Jr. as Dr. Richard Webber
*Sara Ramírez as Dr. Callie Torres
*Kevin McKidd as Dr. Owen Hunt
*Jessica Capshaw as Dr. Arizona Robbins
*Sarah Drew as Dr. April Kepner
*Jesse Williams as Dr. Jackson Avery
*Camilla Luddington as Dr. Jo Wilson
*Gaius Charles as Dr. Shane Ross
*Jerrika Hinton as Dr. Stephanie Edwards
*Tessa Ferrer as Dr. Leah Murphy
*Patrick Dempsey as Dr. Derek Shepherd
===Guest Stars===
*Jason George as Dr. Ben Warren
*Mary Pat Gleason as Marge Walker
*Eric Ladin as Victor Brown
*Lorna Raver as Ghost Lady
*A. Russell Andrews as Hugh Davis
===Co-Starring===
*Robert John Brewer as Philip Walker
*Laya DeLeon Hayes as Taryn Davis
*Marcanthonee Jon Reis as Tuck
*Teresa Huang as Nurse Ruth
*Kate Mines as Nurse Gloria
*Grace Rowe as Paramedic Grace
*Louis Carazo as Bartender
*Eddie Navarro as Zombie
*J. Omar Castro as Paramedic #2
*Melanie Jean as OR Nurse #2
===Uncredited===
*Marguerite Moreau as Emma Marling (voice only)
==Medical Notes==
===Marge Walker===
*Diagnosis:
**Leg Wound with Infection
*Doctors:
**Callie Torres (orthopedic surgeon)
**Meredith Grey (general surgeon)
**Stephanie Edwards (surgical resident)
*Treatment:
**Surgery
Marge's son, Philip, brought her into the hospital when she said she had a bug bite that got infected and was causing her pain. Marge is scared of hospitals, so he had to drag her in and she repeatedly tried to leave. When Stephanie asked, she was told that the bite had happened fourth months prior. An examination of the wound revealed maggots. To make Marge more comfortable, Meredith gave her a sleep mask to wear and asked her about Halloween. In surgery, Callie discovered that the maggots had helped minimize the infection, probably saving Marge's leg.
===Ghost Lady===
*Diagnosis:
**Inspiratory wheezing
**Asthma
*Doctors:
**Shane Ross (surgical resident)
**Alex Karev (pediatric surgeon)
*Treatment:
**Oxygen
**Inhalers
She came into the ER looking for Heather Brooks. Shane asked her and she insisted on waiting until Heather could see her. After the lady disappeared, Shane was looking for her. Stephanie informed him that Heather used to treated unhoused and uninsured patients. Alex found her in a hallway while searching for Taryn Davis and noted that she had inspiratory wheezing and told a nurse to put her on oxygen. When she arrived back in the ER, Shane took over her treatment. He admitted to her that Heather had died and said that he would be her doctor now and she could come in and find him when she needed more inhalers to treat her asthma.
===Taryn Davis===
*Diagnosis:
**Adrenal Insufficiency caused by infection
*Doctors:
**Alex Karev (pediatric surgeon)
**Jo Wilson (surgical resident)
*Treatment:
**D10 Normal Saline
**Hydrocortisone
Taryn's father brought her into the ER with stomach pains and vomiting. She was also febrile. She had an elevated white count and imbalance electrolytes. Further testing revealed that she had adrenal insufficiency due to an infection she contracted while in Brazil with her father on a business trip. Taryn began wandering around the hospital in search of trick or treating when the ghost lady scared her, causing her to go into shock.
===Zombie===
*Diagnosis:
**Situs Inversus
**Gunshot Wounds
**Drug Use
*Doctors:
**Cristina Yang (cardiothoracic surgeon)
**Owen Hunt (trauma surgeon)
**Stephanie Edwards (surgical resident)
**Leah Murphy (surgical resident)
*Treatment:
**Lorazepam
**Haldol
**Surgery
He was brought into Grey Sloan Memorial Hospital with several cop-inflicted gunshot wounds after mauling Victor Brown. Two of the wounds were directly over where his heart should have been, confusing the doctors until they discovered that he has situs inversus, meaning his heart was on the other side of his chest. While he was being examined, he bit Leah Murphy hard enough to break her skin. Owen shared the case with Cristina and they operated on him together.
===Victor Brown===
*Diagnosis:
**Facial lacerations
**Stroke
*Doctors:
**April Kepner (trauma surgeon)
**Jackson Avery (plastic surgeon)
*Treatment:
**Surgery
Victor was brought into Grey Sloan Memorial Hospital after being mauled by another person. While Jackson was tending to his facial wound, Victor had a stroke. April and Jackson took him into surgery to repair his carotid artery, which was damaged in the attack.
===Richard Webber===
*Diagnosis:
**Pancreatic pseudocyst
*Doctors:
**Miranda Bailey (general surgeon)
**Meredith Grey (general surgeon)
**Jo Wilson (surgical resident)
*Treatment:
**Pancreatic cystogastrostomy
Richard decided that he wanted one of the residents to operate on him and he wanted Dr. Bailey to choose which one would do so. After she expressed doubts that any of the residents could handle it, he fired her and gave the choice to Meredith Grey, who chose Jo.
===Leah Murphy===
*Diagnosis:
**Bite
*Doctors:
**Jo Wilson (surgical resident)
**Stephanie Edwards (surgical resident)
*Treatment:
**Post-exposure prophylaxis
**Infectious disease testing
While she was examining the "zombie" patient, who was actually a drug user, he reached up and bit her on her shoulder hard enough to break the skin. While Jo and Stephanie were treating the wound, Stephanie found a tooth. Bailey informed her that she needed to run an infectious diseases panel (including rapid HIV) on herself, the man who bit her, and the man whose blood was in his mouth. Her initial tests all came back negative, so she just had to go back to get tested in six months.
==Music==
Song 	Performer 	Scene
"Change" 	Banks 	
*Marge tells Callie that her room doesn't look like a hospital room and not to miss Halloween with her kid.
*While scrubbing out, Cristina tells Owen she'll go to Meredith's party and talk to her.
*She gets a text from Meredith.
*Jo kind of apologizes to Alex as he treats a patient.
*Victor wakes up and starts to freak out about zombies.
*April explains the zombie to Victor, and tells Jackson that that's how you shut someone down when they're spinning out of control.
"Sun" 	Sleeping at Last 	
*Leah sits on a bench, and she has been crying.
*Arizona joins and comforts her, and tells her the story of her first needle stick. 
*Shane treats a patient and tells her that Heather died, which is why he'll be her doctor.
"Inner Ninja"	Classified feat. David Myles	
*Richard asks how the surgery went.
*Meredith lets Jo explain it as she sneaks out.
*Stephanie wears a clown costume, while an excited cowgirl Leah tells them she's hepatitis free.
*Jackson tells Stephanie she should've listened to him.
*Meredith, Derek and Arizona are ready to take butterfly Zola and pumpkin Bailey trick-or-treating.
*Callie and space princess Sofia join them.
*Shane buys Cristina and himself a tequila.
"Change" - BANKS
"Sun" - Sleeping at Last
"Inner Ninja" - Classified feat. David Myles
==Notes and Trivia==
right|300 px
*This episode's title originated from the song , originally sung by Michael Jackson.
*This episode scored 8.94 million viewers.https://web.archive.org/web/20131103194116/http://tvbythenumbers.zap2it.com/2013/11/01/thursday-final-ratings-the-vampire-diaries-the-millers-sean-saves-the-world-parenthood-adjusted-down/212916/
*Many of the characters were dressed up for Halloween:
**Cristina Yang put on a hat at Joe's bar to look a little dressed up like a witch.
**April Kepner told Callie that she'd dress up as a Velveteen bunny for Matthew's thing.
**Jo Wilson dressed up as Tinkerbell.
**Shane Ross wore a ninja costume.
**Stephanie Edwards was dressed as a clown.
**Leah Murphy was dressed as a cowgirl.
**Ben Warren impersonated a Zombie.
**Taryn Davis wore a witch costume.
**Little Tuck was dressed as a mad scientist. 
**Zola Grey Shepherd was dressed as a butterfly.
**Derek Bailey Shepherd wore a pumpkin outfit.
**Sofia Robbin Sloan Torres was dressed as a space princess, combining the princess and astronaut costumes her mothers made for her.
**Several trick-or-treaters were shown, and shown costumes were zombies, witches, princesses, Cleopatra and a ladybug.
*Marguerite Moreau makes an uncredited voice-only appearance as Dr. Emma Marling when Owen calls her and her dialogue can be heard by the audience.
*Goof: In Map of You, the interns have just passed their intern exam and are 2nd-year residents, which means it's early July. In this episode, it's Halloween (and so it takes place at the end of October), which means four months have passed instead of the said three.
*Goof: When the camera position switches as Meredith and Alex talk right before she heads out to go trick-or-treating, the cupcake box alternates between being open and closed.
==Gallery==
===Episode Stills===
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===Behind the Scenes===
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==Quotes==
:Cristina: You're having a party at the house?
:Meredith: Yeah, Alex is letting us use the house to trick or treat from because we have no neighbors around were we are, so I invited a bunch of families from the daycare. He didn't tell you?
:(Cristina shakes her head.)
:Meredith: You should come!
:Cristina: It's fine.
:Meredith: Right, well, you don't wanna be around a bunch of kids hopped up on sugar anyway, right?
:Cristina: Right, cause I hate children...
----
:April: Matthew has this thing, I'm going as a bunny.
:Callie: Playboy?
:April: Velveteen.
:Callie: Needs some work.
----
:Shane: I'm looking for a crazy lady with weird eyes.
:Stephanie: Too soon, Shane.
----
:Arizona: (to Leah) My first needle stick happened on a Tuesday. It was the second month of my third year in my internal medicine rotation. And my patient was suffering from end-stage AIDS. We had just switched over to these retractable needles. And when I went to put his into the hazardous waste, I didn't retract it right. And it jammed right into my palm. And my whole body went cold. And I had never felt fear like that in my whole life. Right now, it's not the time to be easy-peasy.
----
:Ben: Tuck wants to be a mad scientist tonight. He should have one of those head mirror things.
:Derek: Well, I have a brain in a jar.
:Ben: I want to give him a costume, not a nightmare.
----
:Stephanie: Dr. Webber wants one of us to do his surgery today.
:Richard: Not you. No offense, but I heard you walked into a wall this morning.
----
:Ben: Go work. I'll figure it out. You just come to me at the end of the day with that face, and that body, and the... I'll figure out what to put on it.
:Miranda: It's a holiday for children, you know.
----
:Shane: I'll be your doctor now.
:Ghost Lady: She was a very good doctor. Are you as good as she was?
:Shane: No. But I will be.
----
:Stephanie: Maggots.
:Callie: Gross!
:Stephanie: Writhing and pulsing.
:Meredith: We know what maggots are.
:Stephanie: At first, they were a little bit blurry because my eyes, I just had eye surgery, ...
:Callie: What? What are you doing here?
:Stephanie: I'm fine.
:Meredith: You shouldn't be seeing patients.
:Stephanie: But I wanna be helpful.
:Meredith: Great! Then you can go to the store, and buy some Halloween candy! Name brands, none of those smartees or candy corns.
:Stephanie: But I'm not surprised to drive.
:Meredith: Luckily, someone invented the bus pass.
:Callie: Come on, Grey, you're not gonna make her take a bus.
:Stephanie: Thank you, doctor Torres.
:Callie: There's a shop just up the street. You can walk.
==See Also==
de:Nervenkitzel
fr:Frayeurs nocturnes
Category:All Episodes
Category:GA Episodes
Category:GA S10 Episodes