Magiz grunts and follows Tahazu's point.

"I dunno. This seems very suspect.
There were no sounds of cave-ins from in here.
And where a man would come from, I don't know.
I'll dig, but Bam should stand by with his maul."

If Bam is willing to stand watch, Magiz will start using the butt of his glaive to lever the rubble off of whatever's beneath.