He still hasn't left any tracks in the flour. I think he doesn't want to come out because there's almost always someone nearby. Or maybe it's too cold.
Snakes feel the vibrations from when we merely walk on the floor, or close cupboard doors, and yes, your physical presence may inhibit him as well. Even a snake that is used to being a pet will rely on their wild instincts when they are free to roam. He will naturally be afraid of you too, but it's not "personal".
They normally lay low until they are hungry or thirsty, & I believe you said he was fed several days prior? So that suggests he won't be hungry for a while, and assuming the floor & walls are chilly, he may very well decide to "hibernate" for a while, possibly a few months. I agree that he may be in the wall, but nowhere near your dishwasher by now. You'll need patience & luck to get him back. Remember too that he's apt to be more active at night: if you (all) stay out of the room with lights off (like right before going to bed), you might tiptoe back to check with a flashlight. They also smell water, & maybe a small bowl of water would lure him out too, but again, it might take a while- maybe try that in a week or two?
For future reference, I want to share an observation that goes back to the very first snake I ever kept: I lived in a condo then, & let my snake out on the carpeted floor for exercise & to see what he'd do. Time after time, he unerringly headed for the sliding glass door, because he could smell that tiny bit of fresh air that leaked in and it obviously got him curious, even from way across the room. So any holes in your walls have the same effect, as snakes have an incredible sense of smell. That is why others have lost snakes in their bathrooms, because there is often extra space around where a pipe comes thru the wall: a snake will head right for that.
It's possible that some other tiny hole will allow him to escape to outside the house, but I hope not. Snakes do learn their way around & I hope instead that he finds his way back inside.
Years ago I got a yearling Everglades rat snake from a pet store in trade for one of my hatchlings: this was a snake they had sold as a hatchling to someone locally, but the snake escaped & spent months loose before they were able to catch it. Then they no longer wanted it (-that might have been a parent saying "no more pet snake if you can't contain it"?) & returned it to the store, where it was a little feistier than the store was comfortable with.
He was just scared, & he was a great pet that I was very happy to have.
