Ball Python escape, could he have gotten out of the house?

[KaijuSpy]

My ball python was last scene in his tank last night. I felt like something was wrong this evening and asked my partner to check on him - he had escaped from his tank, it must have been sometime before this afternoon as I sprayed his tank to up humidity - and then closed the door. I can't remember if the door of the tank was closed properly or not when I got there. We have searched all the nooks and crannies of the house and can't find him.

The issue is that the back door has been open for a lot of today and we're fearing that he may have left the house and be gone forever. My HOPE was that him being nocturnal, he wouldn't leave the house while it's bright and sunny outside - but I really have no experience with this situation. I have moved his tank on the floor, - with the doors open in the hopes that he is drawn to the ceramic heat emmiter, and I have set up flour trails that he can disturb, and left his water just outside the tank.

How likely is it that he would have escaped out of the back? I checked the garden, behind the shed and under some of the rubble, and checked the neighbours garden and shed and wasn't able to find him, although thats not to say he couldn't have also escaped the garden.

Thank you in advance for the help. We've had him a year in two weeks time and have never dealt with an escape before.