She thinks she hears something, directing a questioning look at Cloud's back on the stairs. But honestly Cloud is someone who in her opinion gets exasperated easily, so she doesn't pay it any especial mind.

The door is a completely separate matter once she sees what's past it. Her seal would have worn off completely by now...and the monsters are all gone? She's not one to be a pessimist but that sight is not a reassuring one.

"Um..." Aerith's just going to carefully shut that door. And bolt it in case. "I don't really want to go out that way. How about we try...that one?"

Most shops have more than one door, after all: a front and a back is typical, and the back is what Aerith points out now.