Mine are both very offended by poop, to the point where they'll be on top of the hides trying to push the lid off the bin to get away from it. What substrate is he on? When I had mine on paper towels I had to clean 2-3 times per week, but the upside was that I'd take the snake out, pop them in my sweatshirt pocket, do a quick clean and put them back, and this quickly got both of them used to being gently handled for short periods, to where they'd curiously climb out of the pocket and onto my arm, and eventually up onto my shoulders on their own. Rather than leave him alone or clean while he's in the tank, maybe try keeping him close to you but safe while you clean up so he gets used to being around you? He might wind up feeling calmer in the long run.