In addition, how did he know that any of them would still be alive by the time he got back? He had to have been gone for at least ten minutes (because we know the cleric cast Sending before he returned)--he knew Belkar was sick, so he would have had to assume that Haley, Celia and his old friend could survive against the attack of the entire Guild for that time. Doesn't seem likely, and if the Guild had had any tactical sense at all (e.g. NOT sending all the lowbies in first while the high rankers held back) then it wouldn't have worked.

The only evidence we have that Pete might have been trying to mount a rescue is his own words when he was pinned to the ground by a sword through his foot and had a man advancing on him with murder on his mind. I don't think anything he said then can really be relied upon as truthful--he was trying to save his own hide!