I'd also be up for a new take on this. Maybe a relapse when Bucky is living with the Avengers post-CACW? Or some alternate continuity where they find him before CAWS?
Maybe they keep him in a holding cell until they are sure he won't attack them. They try to make it comfortable, but that just makes him more sure of what's coming. Or they give him a room adjourning Steve's so he can keep an eye on him, but Bucky thinks that means he's for Steve to use...
Or for whatever reason, he wakes up strapped down in the medbay, all the Avengers around him...