When article says "..it's actually behind you" that leads me to believe that if you're staring at those signs then you're actually at B45. I'm not sure off the top of my head how you'd put B45 on those signs in a clear way. If B45 is at the intersection of two hallways then it really shouldn't be on either sign but then where should it be?

You'd need a segregated entry for B45, or just omit it entirely