Finn and Poe's friendship is legendary across the galaxy. The Stormtrooper who broke through his conditioning to escape with the Resistance Pilot, both later becoming partners in crime and completing various Resistance missions together. Everyone, good and bad, knows the story of Finn and Poe.
When they're picked up by bad guys (does not have to be First Order but can be) they are recognised and their reputation is used against them. They try to make them fight each other, force them to watch each other being beaten or sexually assaulted. Everything that can be done to take advantage of their affection for each other is, until they're thrown a single blaster and told one of them has to kill the other, or they both die.
If/how they get out or not is up to anon, but OP would like no character death please!
Gen. Finn and Poe are each others weakness [non-con mentions]
When they're picked up by bad guys (does not have to be First Order but can be) they are recognised and their reputation is used against them. They try to make them fight each other, force them to watch each other being beaten or sexually assaulted. Everything that can be done to take advantage of their affection for each other is, until they're thrown a single blaster and told one of them has to kill the other, or they both die.
If/how they get out or not is up to anon, but OP would like no character death please!