Given scene/plot descriptions from movies or TV shows, and given a specific question about the scene, summarize the question into a title

[EX Q]: I've never understood how Kirk, Spock, and Bones got back to the present at the end of “City on the Edge of Forever”. Going back to 1930 is simple enough, they stepped through the portal at the right moment, but there was no portal on their end! How did they get back?  Finding an answer is proving to be difficult because even after trying numerous search-term permutations, I only managed to find a single mention of the discrepancy.  I can understand if maybe they wanted to focus on the emotion and stuff of the episode, but it's a science-fiction show, and this was one of the first incidents of time-travel in the whole franchise, so getting back is a fairly big issue that can't just be glossed over.
[EX A]: How did they get back in “City on the Edge of Forever”?

[EX Q]: I understood the reason behind her wearing those bands around her neck and wrist, when the director of the mental hospital revealed she had scars in her wrists and neck. She used those bands to cover those scars. But I could not understand what could be the reason behind her wearing weird dresses all the time. We saw her wearing a particular type of dresses instead of wearing casual dresses to go to school. Besides that, she all the time wore that type of dresses. I think she wears the particular type of dress for a specific reason. What could that reason be?
[EX A]: Is there any particular reason for Esther to wear the dress instead of casual dress?

[EX Q]: In Person of Interest, in "The Day The World Went Away", Finch's cover identity is exposed after he visited a cafe he brought Grace to. How did Samaritan establish the link between Professor Whistler and Harold Finch? As far as I know, Samaritan knows:   A person who looks like Finch used to come to the cafe A person who looks like Finch used to order the same thing   That, to me, is not enough to conclusively prove that Professor Whistler is indeed Harold Finch. What other information could Samaritan possibly possess to help it expose Finch's cover identity? Was it the fact that Finch was talking to The Machine?
[EX A]:
How did Finch's cover identity get blown?