Where do you get the impression that it's an alternate universe? The only thing we know from the previews is that something has somehow changed the interiors of the ship and changed everyone's clothes and personalities, though M'Benga apparently keeps his personality and memory. All of this can have another explanation other than alternate reality.So this week's episode shows the usual story where the heroes are suddenly in an alternate universe and only 1 of them remembers the real timeline (in this case it seems to be M'Benga).
All the more so once you factor in behind the scenes information revealing that
everyone has somehow turned into characters from the book M'Benga reads to his daughter.