Please forgive me if this question has already been raised and answered, I’m new to this board and couldn’t find the answer.
In season 1 and most of 2, anyone that came to this universe had to be put in a chamber so their bodies could acclimate, example, Walternet when he came to get Peter. Yet Walter went over at the end of season 2 and adjusted and Faux-livia came to this universe seamlessly (as well as Peter when he was a child). Was there some kind of justification given by the writers as to why they could jump universes with no health issues?