true ending question (spoilers, obviously)

I've followed all of Dr. Beanie's instructions and saw the credits roll. I saw that there's another ending that can happen if you don't >!detonate the nuke!<- and that you can get it by redoing the >!jar of radiation!< questline that requires you to redo all of act 1 and 2.

however, it's been about a week in game and i haven't been given another jar of radiation - is it just an item that you get from turning in mutated cats to dr. beanie that I have to wait to get randomly??