It happened again.

I forgot to fully close the door to Asriel's enclosure after misting it down, and he decided to go on a little stroll.
Typically I don't panic when he goes missing-he's escaped on me twice before, and I found him in no time. (Once he was nestled in the radiator, the second time he was behind my bed) However I've since then changed rooms, I am no longer in the bigger room and now in the much smaller room. I thought finding him would be a walk in the park-it's a small 7ftx9ft room, the gap under the door is covered, there are no holes in the wall, easy-peasy.
I cannot find him anywhere.
I've ripped that room apart. There is no way he could've escaped the room, as my door is closed nearly all the time. I've checked behind his enclosure, under the stand his tank is on, the entire perimeter (once again, a very small room), in drawers, thoroughly searched the radiator, behind all my plushies against the wall, in any open bags, hell I even tore open a garbage bag. I also went through his enclosure, obviously not there.
I checked around outside the room, but I doubt he got out as the gap between the door and the floor is very small and the house is a lot cooler than my room. I tried the flour and tin foil trick, to no avail.
Does anyone have any other tips or tricks? I'm at a loss, I thought I would've found him by now. He's not a climber, and is quite lazy.
Any help is greatly appreciated, thank you.