My cat just found a warp pipe

I keep the bedroom doors shut (there are two: one from the living room and one from the room-that-has-no-function) at night so the cats don't frolic and make noise above the downstairs neighbors' bedroom so they can actually sleep like normal people.

Just five minutes ago, the cats were climbing all over my computer chair while I sat here uploading photos. Then I heard a noise to my left, near the bedroom door. I looked over and saw a little black paw sticking out from beneath the door. Just feeling around. You know, just to see what it could catch.

I opened the door — it had been latched — and there stood Sally, like, WTF, dude, you blew my cover! I checked the other door to see if she had pushed her way past it. No dice; my giant laundry hamper, heavy with dirty clothes, was still in position where I had scooted it earlier to make sure they didn't nudge the door open.

Unless she can get through a 1.5-inch crack under the door, she must have discovered a wormhole in here.