Wall of Stone handling in Hold the Lighthouse encounter

[Tobold]

The Golden Icon of Urim that the players find in the Sea Cave encounter can create a wall of stone 15' wide, 10' high. That would fit perfectly in the area between the sea wall and the outside the lighthouse area in the "Hold the Lighthouse" encounter. Can the players use that power if I run the encounter as a skill challenge? Or does the short duration (until end of next turn) prevent the wall of stone from doing anything useful in these 1-minutes skill challenge rounds? How would you handle that?

 

[RangerWickett]

Maybe let it automatically negate any 'remove barricade' efforts the enemies can take for one turn, because it completely stops them momentarily. I'm all for PCs having an easier time of things if they're clever.