I'm sorry, but I have to be "that guy." I really get annoyed with people who feel the need to bring their entire hygiene routine to the gym with them. That includes shaving. I totally understand packed schedules, and I understand wanting to workout in the morning and shower and be ready for work. But, the gym is a place to work out. (incidentally, it's also not a place for cell phones, lengthy conversations with your workout partner/bro, a place to scope out the other members, a place to find dates, or a place to do the butt-flossing with a towel). The gym bathroom is a shared resource, and it's also kind of an icky place.

First off, even at a gym with multiple sinks (mine has ~7), if you're setting up for a wet shave, you're essentially taking up two: one to shave in, and the one next to you that nobody will use (like the no homo urinal spacing). Plus, if you're using a sink next to the wall, you're probably also blocking one of the paper towel dispensers or hand dryers. That's just plain rude.

Second, I don't know about you, but I think that gym bathrooms are one of the most disgusting places I ever go. Athlete's foot fungus and MRSA run rampant at gyms. No matter how clean the locker rooms seem, the reality is that there are dozens, if not hundreds, of sweaty nasty dudes sharing the same area as you throughout the day. Do you really want to be touching your face, possibly with little nicks, after touching anything in a gym bathroom? Hello, I'd like you to meet Mr. Staph infection.

Third, I get really nervous even when it's just my wife walking behind me when I shave. I use a safety razor, so I know that the damage would be minimal if she accidentally bumped my elbow or something, but I still want to avoid that if at all possible. I would never take the risk at the gym where there's a lot more foot traffic and the people couldn't care less if they accidentally bump you.

TL;DR: Just don't shave at the gym.