Alright, I'm going to pop in with speculation-fodder, which is for forumites only! Yay!
All of the 'alternate realities' that are, have been, or will be displayed are 'what ifs'. They are going to be What Ifs of varying degrees of likelihood (at least one upcoming one is way the hell out the other side of probability), but each are based on one or more events in the past having resolved differently. If you can spot what the change is, you can usually figure out what caused everything to be different.
For a freebie, I will give you a hint, and it will be referenced in future comics - before the reality bubble, Lucky and Mayfly are suited up and heading out. In the reality bubble, only Lucky is suited up, and Nadia is wishing him luck.
(I am a terrible speculation-feeder.