OOC: Two questions:
1) Can Shai use Entangle in this setting? Okay, obviously he can cast it, but will it have any effect? The descriptive text talks about plants, which wouldn't seem to be too prevalent here, but I find it odd that same text doesn't say anything about requiring a natural environment to work (most of the fire spells explicitly say they don't work in water, for example, even though that might seem like common sense). I always sort of thought whatever plant life was lingering under the stone would spring up and do some binding, but I'm probably biased.
2) Depending on the answer to 1) above, is more of the swarm inside the room, or on top of the party?