he'd probably ask what level Domri's are and pick his party accordingly, actually

And no, he doesn't. Just because he's probably not a big fan of cities doesn't mean he thinks they should all be destroyed. :|

....though to be fair, summoning magic exists in Geddoe's world (and is actually part of a plot point in his canon) so as soon as he realizes those are summoned monsters he'd go straight to the most logical option: take out the summoner.