Finding Smalltown
Verzeg, who is timid and fearful if he has time to think on things, is far too focused on the serious danger of the creature above to be scared enough to flee. It starts to dawn on him that this thing might be quite smart, smart enough to have set a trap. He knows that there's variations in intelligence and even things that can't speak or have families can be clever enough to out-think those not paying attention or those who let pride make them think they're smarter than dumb animals. Those individuals who do that get eaten in The Big Rubble. Verzeg has the luxury of being an extremely intelligent example of a notoriously stupid category of trolls and thus has a long experience of what stupidity can do in the face of threats.
Crouching quietly, he considers the situation. His troll senses give him a pretty good idea of the area. He only knows these things are savage ambushers, not how fast or how big they are. He quietly scans the area, making sure nothing is creeping up on him or in case there's more overhead shafts he hasn't sensed yet.
It occurs to him that either he carefully removes what he assumes is the spear before the monster can react, or he quickly destroys the creature before it can attack - something he's unsure he can achieve - or he distracts it. The problem he faces is he doesn't know how these things sense, he assumes they sense just like he does so if he does anything it must be utterly without sound. That means he can't use spells to prepare.
Slowly reaching down he softly feels around for a few pebbles, being extra sure not to create any sound. If he finds some he'll quietly toss the pebble some distance further down the the gallery and see what happens, readying his spear to strike if the creature drops to the ground and rushes him.