I have to think the guy briefly seen striking out the days on a wall has to be Jack. At least that would give an explanation to his even more bizarre than normal behavior. And it really has to be to redeem his character, as I’m sure Days wants to reunite him with Jenn.
but who would be holding him prisoner? First ones to come to mind would be the DiMeras, but why????? Wonder if this has anything to do with E.J. taking that money out of the safe? Just speculating!