Washers take time to fill up, she was fleeing the scene. Even if she stuck around waiing for the washer to fill up and the cycle to start to make sure she didn't hear a camera clunking ariund inside

/), the idea is that it was tangled up in clothing. It wouldn't necessarily make any noise until it shook free or the spin cycle started. The woman could have put the laundry in, turned on the water, hit start, and bolted. I'm not sure why we're assuming she must have stuck around and not been in a complete frenzy trying to get everything sorted and get out before the room mates came home.