Excuse me

This post is not about Ethiopia but about the Japanese language, although it took place in Ethiopia.

As most people know or can imagine, the Japanese language is full of polite niceties and phrases that you would never hear in English. For example, at a full-service gas station (a rarity in Japan, but attendants are still common), they will happily open your car door for you so you don't have to bother opening your window. They will then take payment and give you change and so on, and just before closing the door they will actually announce in a friendly, almost jovial tone, "I will close the door!"
To frame the beginning and end to any activity, it would not be all that odd for someone to say, "Start!" and then, "That's all" to signal the end. In the same way, when entering someone's office, it is commonplace to say, "Excuse me" and then repeat the same phrase in the past tense when leaving the room.
Today in the men's room, my coworker surprised me by saying, "Ojyama shimasu", which means something like sorry to bother you or sorry to get in your way as he stepped up to the urinal next to the one I was at. This is a phrase you would normally use when entering a friend's house and is merely a formal saying like the one above, repeated in past tense when leaving. It's never used in the bathroom and I knew that he was saying this to simply signal that he was in the bathroom and about to step up next to me, maybe so as not to surprise me. I probably didn't need to say anything, but my immediate response was, "Ojyama shiNAI de!" (DON'T get in the way!) which, considering the situation, I thought was the appropriate thing to say. Luckily, he got the joke.