ATB escapee

A few weeks back at a local convention, I came across a stunning yearling ATB. Had to grab it and the seller seems amazing. All was going well, his humidity and temperature are looking good. He's supposed to be in QT, so I wasn't overly concerned when he wasn't basking. I'd assumed he was just in a hide, and because of how high strung he is, I didn't disturb him. This was a few days ago. I was beginning to get worried as he hadn't basked in a while, and went to check for him. He is gone.

I went through the area around his enclosure for a good twenty minutes, and caught no sign of him. I'm sure he's been out for a few days at this point. I will be THOROUGHLY going through any and all areas he can get to. I've checked areas where he might go to find warmth but found no sight of him. I know they depend decently on water, and will be placing dishes around in hopes that he can get to them and that dehydration wont kill him.

All of my other snakes are thriving and have not escaped their enclosures. I believe I underestimated how much force the thing could muster due to its small and slim build. I will not assume that again. If anyone has any tips on how to lure him out or areas to check please mention them. He's still very new to me and hasn't taken a meal yet, his system is empty.

He has been found, and he is okay. So thankful that our cats didn't catch up to him and that he didn't get hurt in the process.
We covered his qt enclosure with a towel as to lower stress as much as possible. Going to leave him alone outside of cleaning water dish and checking for droppings. He seems to be going into shed, some spots of it torn (not the actual scale but the shed) but this is still before it was ready to come off. I think I will likely have to assist in his shedding this time around due to that.
During the handling he was very persistent on trying to empty his bowels on me, but he has nothing to empty. I am scared that he may prolapse himself due to the pushing he does whenever interacted with. He's quite the scared little thing and I'm hoping he'll thrive with me.
Again, extremely thankful that he was found and is safe.

So, how did you find him?

Flashlight and just happened to get lucky in seeing him. Would've never thought he would be able to get that high up.