After fighting BGH251F2 the second time in FH why when its destroyed and falls into the water Selphie and the rest of the missile base team crawl out?

This is my third time playing the game fully through and its a question I've always asked myself. Obviously they fought it at the missile base before the base was destroyed. Did they use it to escape the missile base& had to then pretend to be galbadian soldiers operating it?

Where they taken prisoner?

What do you guys think?