Ambrus, I'm sure you know that taking 20 on a room 10 x 50 will take quite some time. At 2 minutes per 5 ft square, it'll take 40 minutes to do the whole cave. The others may well figure out how to get in in the interim, so if it works out that someone else discovers the gnomes' cubby while Maelicent is making his very thorough scour of the cave, please be prepared.