Holy Word says:
And then gives a list of effects such as deafened, blinded, etc.1Any nongood creature within the area that hears the holy word suffers the following ill effects.
It's only the banishment of outsiders which does not require the target to hear. That probably won't have an effect on this battle, though.
So Belkar heard the spell. The trap door he was hinding behind was probably the same one the sawblade trap came out of. That trap was triggered just before Durkon said the Holy Word, so the door to it was probably still open. That would let Belkar hear it. If not, then Belkar probably kept the door open a smidgen to see what was going on, so would have heard the Word that way.
Before this strip was posted, I was contemplating starting a thread speculating on what was going to happen in the next round the the ambush. The laws of drama indicated that Belkar would be the next to get involved and that he would enter from above.
At first I thought of an elaborate scheme where Durkon creates a small platform near the ceiling by means of Stone Shape. He would borrow Belkar's Ring of Jumping (and shed his armor) to get up that high (it's a touch spell). But I also thought of an alternative where Belkar hides in the same space the sawblade trap came out of. (I now wish I'd started that thread, since that was what happened.) I figured Belkar could avoid the effects of the Holy Word by wearing earplugs. But then I thought the darkness from the smokestick would make it too difficult for him to see where to jump. OK, I was wrong on these last two items.
Someone upthread (sorry it's late, and I don't have time to hunt for the post) claimed that no one thought that Belkar would be subject to the effects of Holy Word. Not true. At least one (and I think several) people pointed out that one of the spell's limitations was that both Belkar and V would be subject to it if Durkon had cast it in their presence. Interesting to see how the giant turned that limitation upside down...
So the next person to enter the fray should be Elan. Unless Roy has him tied up and gagged so he didn't ruin the ambush by loudly proclaiming his move silent roll... Assuming he isn't, where is his hiding place?
Roy should be getting involved but he doesn't seem to be moving anywhere. If he does move down the corridor, he'll first encounter the mummies. I expect he could take them all out with one or two Great Cleaves. Or possibly he could just run past them, since their controller, Malack, can no longer see them and order them to attack. Would they attack on their own initiative?
1 I do wonder about the last entry in the list of Holy Word effects. Anyone more than 9 levels below the caster's level are "Killed, paralyzed, blinded, deafened". Aren't the last three kind of superfluous? Or do they apply to the spirit of the character in the afterlife?