What is going on with my Hermit Crabs? Help!!!?

I woke up this morning and decided to give my hermits some water etc when to my horror I discovered that one of my guys (the smaller of the two) was dead :( I picked its shell up and and saw that he/she was hanging all the way out of the shell and he/she seemed pretty mangled. I examined him/her closer and then realized there was a little baby one behind him in his shell! So was my little hermit killed by some little baby invader? Now there is a bigger hermit crab in there and these two would sometime fight. I doubt that the bigger hermit impregnated the smaller ones shell so as to have the smaller one be eaten out of its shell. I am super confused. I guess the silver lining is that I have a brand new baby hermit crab in place of the one that was tore from this cruel world so callously. please someone...Help me understand this phenomenon