They told her that she would be interrogated for a period of time, so they could determine if she was still sane enough to fight for them. Rey doubted this strongly, but agreed to participate, if only for sport.
And guess who was going to interrogate her? Motherfucking Kylo Ren. Him, of all people. The one person in the entire First Order who Rey wanted dead more than anything. The one person Rey knew better than anyone else, though she never admitted it.
The one person who Rey couldn't lie to, no matter how much she wanted to.
… Fuck.
When Kylo Ren heard the news, he told them to choose someone else for the interrogation. Anyone would be more fit for the task them himself, for fuck's sake.
But apparently, the First Order thought it was a brilliant idea to put two bitter enemies together in a room for several hours.
Kylo Ren was sure that they would end up killing one another after only the first few words. But he had no choice but to accept the task given to him, so he resigned himself to spend the next few days arguing until his throat was sore, and with some kind of stuck-up vigilante bitch to top it off.
He would be lying if he said he looked forward to it.