Doctor Princess is Betty (Simon Petrikov's fiance for all those who dont know.). This is only a guess, but they made susan strong, who made finn. she felt herself losing her mind in the hyooman village, so she brought baby finn up to the surface, leaving him at a rendevous point, where susan's old friends Margeret and Joshua (again, for those that don't know, jakes parents) were to pick him up and raise him. They had no clue what the baby looked like so were surprised to find the boom boom baby on the leaf. Doctor Princess, meanwhile pretends to forget the ice king, knowing the ice king wouldn't put the thought of Doctor Princess being Betty in his head. Is it just me thinking this?