Why didn't Harry summon the marauders map when he got stuck on the fake step the night where Moddy 'saved' him from Snape?

When Harry was returning to Gryfindor tower after having been on the prefect's bathrrom trying to solve the clue insided the egg, he got stuck on a fake step on the stairs, making his egg and the marauders map fall out of reach, now Harry had just learned to use the summoning charm and been very successful at it, so in the book it says that he ws a just a few inches away from the map but couldn't reach it. Why didn't he just use Accio and been done with it? We know it played an important part on the fact that Moody woukdnt get discovered.