Will Arrowsmith Will Arrowsmith was a junior science officer of UNIT who acted as the assistant of its scientific advisor Elizabeth Klein during the early 1990s . He was on probation to become a full member of UNIT when he saw an opportunity to prove his skills in the field and decided to follow Klein and the Doctor into the TARDIS , getting involved in the search for the persuasion machine . ( AUDIO : " Persuasion " ) Biography . Before the Doctor . Will was on probation to formally join UNIT . According to Elizabeth Klein , he was very intelligent and his research papers were superb , but his work on the field was underwhelming and poor . He was involved in at least three failed missions in Bangalore , Yarmouth Pier and Mexico City . While he claimed to be trying his best , Klein and members of staff considered him to be more adept at a desk job , disillusioning Will . ( AUDIO : " Persuasion " ) Meeting the Doctor . While on an informal meeting at a pub with Klein , Will noticed the presence of the Seventh Doctor in the pub and informed Klein , fearing a new " blue box incident " . Klein ordered him to inform UNIT command of the presence of the Doctor while she followed him . He asked to come with her but she refused . Deciding to prove himself to her in the field , he directly disobeyed orders and followed her into the Doctor ' s TARDIS . Inside , he explored for a while before realising they had landed and that both Klein and the Doctor had already exited , so he followed them outside . Landing in Dusseldorf in May 1945 , Will went out to search for the Doctor but bumped into Lucas Hinterberger instead . Hinterberger threatened to kill Will until the Doctor and Klein appeared and it seemed to calm him down . At that moment , the Klecht entity informed them that they were planning on detonating a bomb to kill them , so the Doctor gave Will his sonic screwdriver and told him to defuse the bomb . He managed to figure out how it worked , but was unable to cancel the detonation until the arrival of the Doctor . Hinterberger told them about the struwwelpeter and agreed to tell them the location of Kurt Schalk , the scientist the Doctor had come to search for in the first place . After materialising on the Greek island of Minos where Schalk was hiding , Hinterberger became afraid and ran , with Will running after him . When he caught up to him , they both came in contact with the struwwelpeter , but the meeting left them unconscious . After recovering , they went to find the Doctor . When they came into contact again , they learned that the struwwelpeter were actually godlike beings that came from another universe and considered this universe to be corrupt . The struwwelpeter gave Schalk the information to build a device known as the persuasion machine that could manipulate everyone to follow the will of whoever possessed it . The Doctor offered to take the struwwelpeter to another planet that was more beautiful . However , this was a lie so the Doctor could trap them in the planet which he later trapped in the TARDIS ' s star chamber . While this happened , Schalk was taken by the Klecht entity , so the Doctor , Will and Klein pursued him to prevent the persuasion machine being used . ( AUDIO : " Persuasion " ) The Doctor located both Schalk and the persuasion machine being auctioned by an old acquaintance of the Doctor called Garundel to several warmongering species . So as to not make Garundel suspicious , the Doctor sent Klein and Will undercover to investigate the location of Schalk and the machine , as well as to provide the Doctor an opening in Garundel ' s defences for the TARDIS to get through . While investigating , Will started to like Garundel ' s assistant named Ziv . He followed her to discover the weapons ' and Schalk ' s location . He infiltrated the location of the weapons , but got trapped inside it . Investigating it , he found the body of Schalk . When Ziv returned , Will gave the Doctor the signal to land , but was discovered and captured by her and taken along with her in a space ship disguised as a store room . During the escape , Will reprimanded Ziv for her lies and scheming until Garundel remotely disabled their ship . He asked her to travel with them if possible . He also learned that the man in the ship was not really Kurt Schalk . They were caught by Garundel along with the Doctor and the Sontaran battle fleet who had captured Klein . The Doctor escaped to their ship . Will then negotiated the exchange for Klein and learned the dead man being auctioned was not really Schalk but Hinterberger . Schalk used the machine on Hinterberger and himself . Will was saddened to hear Ziv wasn ' t coming . ( AUDIO : " Starlight Robbery " ) They returned to Minos in 1945 and discovered the Dalek s had captured Schalk . The Doctor found them in the planet Azimuth , a planet visited by the Doctor and his companion Ace , while recalling the events transpired there the Doctor mentioned the previous Dalek occupation which alerted the authorities and Will got captured . The Superintendent Qaren who was against the law that prohibited the mention of the Daleks and the occupation took him to meet with Father , there he asked Will to bring the Doctor to him . He returned to the Doctor and Klein but mentioned the Daleks and were chased again while the Doctor went to meet with Father , Klein abandoned Will and left in the TARDIS leaving him to be captured again . Will was taken by a man named Falkus to the Dalek lair where he found Schalk was now leader of the Daleks who interrogated him . When they brought the Doctor to them Schalk was going to torture Will to make the Doctor talk , he told what happened to Klein and that she went to 1945 again to see her creation , the Doctor revealed Schalk to be the biological father of Klein and her creation as a tool for the use of the persuasion machine , at that moment Klein returned in the TARDIS and acted like a Nazi willing to be used with the machine . At that moment Falkus entered the room and ordered the extermination of Schalk , he was sent to a prison cell but was rescued by a duplicate of Qaren and taken with her and Davros to rescue Klein , he tried to reason with her , he recovered the TARDIS key and left to free the Shepard to save them but it reversed and it threatened to kill them , Klein killed it with the machine but sacrificed herself in the process . The Doctor and him realised that it wasn ' t really Klein but her biological mother , they then tracked her to Russia in 1945 , as they were being chased by Russia n soldiers the Doctor called it an adventure . ( AUDIO : " Daleks Among Us " ) Personality . Will was a very introverted man , often acting nervous around other people and indecisive when needed to take action . He was oblivious to the effect his presence and quirks had on others and seemed to have difficulty getting along with other people . When addressing others he was very proper and formal , always addressing Dr . Klein by her title or by ma ' am and seeming to speak with utmost respect towards others . He was very intelligent and logical , being able to comprehend situations and details regarding the lifeforms they encountered . He was also prone to certain compulsions , such as having to record his thoughts both alone and in the presence of others for reflection and relief . He also had the tendency to speak to himself when alone . ( AUDIO : " Persuasion " ) During his travels with the Doctor , he seemed to be able to adapt more to the situations they encountered and started to gain both skill and confidence in field work . By his own claims , he seemed to not be very good regarding romantic affairs , though he was capable of speaking to girls he found attractive , even flirting with and inviting the alien Ziv to travel with them . ( AUDIO : " Starlight Robbery " ) Will was also naively trusting of others , to the point of sharing all information he knew to strangers , some of them unknown enemies . ( AUDIO : " Daleks Among Us " )