Brainy Pete had a silver trophy...

[Amarsir]

This is off-topic (and maybe discussed) but Brainy Pete says to the guildmembers that he just wants to get to his den (where the weapons are) Is it possible that he really was going to mount a rescue?

I felt so at the time. (And actually would have preferred that to the Celia-driven way the arc ended.) But that would mean The Giant set up the rescue and then immediately changed his mind and dropped it without mention. I find that unlikely. So absent any author's indication that Pete wanted to save them, I have to conclude that was never the plan.