I let a door to door salesman use the restroom

Before anyone calls me naive, this is my first house, and I genuinely thought the door-to-door salesman was having an emergency. He didn't have anything with him, and I walked with him to the bathroom and waited nearby the whole time. As soon as he finished, he came straight back out and left.

I checked the bathroom afterward, and there was nothing out of place or anything that looked suspicious. He didn't wander through the house or try to look around. He literally went straight in and straight back out.

That said, it was definitely a lesson learned. Next time, I'll politely let them know there's a gas station just two blocks away. I have no clue why at the moment I had sympathy for the man.

I am pretty worried and anxious can't even work properly. What should I do? Should I just pay attention for next time or call the cops?