Mysterious Cheesy Escape

A shiver crawls down your spine as your hand slowly reaches out towards the ruby, tattered carpet. Something... some unknown voice in your head... is guiding you. Is it trustworthy? You don't know. But you do know that is your only chance to escape this frightening place.

Suddenly you hear footsteps. They're faint, gentle tapping noises, but you have an alarming feeling about it. You quickly slide your hand underneath the fabric and feel for helpful objects... and you succeed. Your fingers curl onto a small and cold metal item and you slip your hand back out. Yes! A key! However, you don't have much time. The footsteps are getting louder and louder, you have to act fast.

You know there are the set of double doors, on the other side of the room. They don't seem like the main entrance, though, so it probably just leads to another room or hall.

However, underneath the carpet you have just discovered a wooden trapdoor (which is - unsurprisingly - also locked). You only have one key but the two doors. You know that the key can only fit in one...