I often have to work in our server room with a colleague, doing things like racking new systems, replacing drives, diagnosing issues, etc. It's a super loud room with around 50 units going at once, so the door is soundproofed. We're supposed to keep the door closed when we're in the room to keep the noise down, but it's making me uncomfortable to be alone with someone else there.
I don't have any reason to think my coworkers would assault me, it's just that this would be the perfect room to do so. There are no windows in the room and as far as I can tell from the damping, it'd be really hard to hear anyone inside yelling for help.
I've tried propping the door open, but my coworker shuts it again and reiterates that the rules indicate the door should be closed. I've said that I'm simply more comfortable with the door open, but that hasn't worked either.
How should I try to politely tell coworkers I'm uncomfortable being alone with someone else in a closed-off room, in case of an assault?