He's not a particularly stealthy guy to begin with. The door comes open easy but noisily, he bumps into a counter with a sharp curse, and his poking around the kitchen is anything but subtle. You might say it looks lived in, but so do all the empty houses. Anyway, he doesn't make any attempt at being terribly sneaking until he crosses into the living room and realizes (like swallowing a weight) that someone's there. He freezes in the threshold, one hand behind his back, ready for his knife.