Read the sign people

There's this single occupancy bathroom on the ground floor of where I work for handicapped individuals. Without fail, at least once a day when I am in there, someone has to try to open the door. That's not the irritating part. See, there's a sign on the actual door, about eye level, that clearly states that there are more facilities next door. There's even a nice arrow pointing to the door next to it that is clearly labled "Womens Restroom"

However, more often than not, the person fails to see this sign and continues to try to open the door grunting, huffing, cursing, because surely there can't be a bathroom for just one individual.

One time, when I left, the lady waiting shot me dagger eyes. I guess she really had to pee. I calmly pointed to the sign and went "There are more restrooms next door." I'm sure she didn't read the sign, but she did have a comeback:

"I thought it meant that there were more in the next building."

Next building? If this many people can't find a sign right in front of their faces, how can they orient themselves inside a building and figure where "next" is, once they go out into the corridor make a right turn, another right to go up the steps and then a left to go outside. I guess techincally the sign would work that way, but I doubt it. However, I'm also baffled at the fact that she didn't notice the chorus of flushes that came out next door. It's not like the registar's office (which is further down the hallway) would make those sounds.