First off,
Awesome comic!
My favorite panel is panel 4 where Z'zdtri fumbles Gust of Wind.

Tarquin's speech does seem a little out of character, but hey, exposition.
+1 to Tarquin for recognizing Durkon's spell. Roy doesn't need spellcraft to recognize Durkon's spell because the ambush implies Durkon and Roy would've discussed using Holy Word before the battle began.

Regarding Belkar, a closed trap door blocks line of effect...
but Belkar (although he was off screen at the time Holy Word was cast) clearly wasn't keeping his trap door closed when we see him on screen. The implication is that he had the trap door slightly open to observe the ambush when the spell was cast and therefore line of effect was not blocked (please note: hearing the spell does not provide line of effect unless, of course, the Giant house rules it). As for Mr. Scruffy, I thought he was epic level

Totally awesome banishment fade away scene!

In response to everyone who thinks the mummies were destroyed by the Holy Word consult comic #858 panel 9. The mummies are ahead of the group and it remains to be seen if any mummies at all were caught in the area of effect. Admittedly, the 40' radius is substantial... so is this hallway...

Belkar's response to being deafened is really very funny because he thinks they cast some sort of Silence spell, and he is using speech to tell Roy about this! This is sort of how all the characters in the comic are reacting.

Nale removing the arrows from his body is a cool detail. Speaking of details, does anyone know what the gray around the arrow heads represents? These arrows are not thick like the first arrow that created the cloud of smoke and there is enough color in the comic that I would expect to see some red if they were flaming arrows... so what is it? Magic arrows is my first thought... but why gray?