Kerlan looks very concerned about the voice. Not only is he worried about being discovered, he is also concerned about what was said. Fealing that he must act now, he motions for the others to follow him as he creeps back over to the tunnel. When he gets there, he casts his Web spell inside the tunnel.
OOC: I'm don't think we have the whole tunnel on the map so I'm not sure where to place the spell.