Downstairs Hallway

After resting up at E. Gadd's lab for a (very) long time, Luigi reenters the ominous building.

Arriving in the foyer, Luigi checks all of the previously locked doors with Chauncey's key, and discovers that the only door that it fits in is the door into the hallway on the main floor. Slowly creaking it open, he walks in and sees a small, round-ish ghastly figure dash through a door.

Follow it!

Ignore it!