I'm not 100% sure but i thought the first time Shin went into seed mode wasn't because minerva was getting slaughtered but because he was angry at orbs actions. I haven't seen that episode in a while though so i could be wrong. And Shin does do everything for himself until he met Stellar. I think she's supose to be the thing that changes him from a selfish spoiled brat into a decent main charecter

P.S. your right masamuneehs but i just had to say my opinion ^^