The light could be another trap, no matter how inviting it seems. Maybe the door is a closet or some place to hunker down until morning.

Nothing happens when you pull at it, nor when you push on it. Finally, you slam all your weight into it and the door is forced open with a loud creak. It's not a closet or room, but a dark tunnel that seems like an endless abyss. Your instincts tell you to turn away, but the noise of the door opening must've alerted something because you hear shuffling upstairs.

Investigate Pretend you never saw it