So while working undercover Reese gets hit on the head and becomes convinced he is the person he's pretending to be. Finch first has to find him, then convince him to come with him, and then try to keep Reese safe (from himself and the people they were after this time) and not have a nervous breakdown in the meantime. I'd love it if the villains catch up with them and Finch finds himself in the position Reese normally occupies - that of protector - because John may still be gutsy and defiant but he doesn't know how to fight or shoot.