PD sanitation concerns

Thanks to all of you that contribute to this site! It’s comforting to have all of you to share concerns with. Here is one I have. There are 2 or 3 people in my family that set up my Dad’s PD cycler. We are all very careful, but I worry when I hear a fan was left on accidentally, the door wasn’t closed all the way, etc. It doesn’t happen often but it’s still worrisome. How high is the risk factor when this happens?