This wasn't awkward for me, but I will share for the other person (whoever they were). Something really bad happened at work, so I went to the bathroom and bawled. My coworker knew what was up, so he knocked on the door and I let him in. We were in there for a while because I just couldn't stop crying (dog related, the only thing that will get me) and after a little while someone knocked on the door. Neither of us thought about it and both said "Just a minute."
I still don't know who knocked on the door, but I'm sure there were a lot of questions after they knocked on the employee only single toilet bathroom with a shower and a male and female employee both said "just a minute."