Police Come From Hallway Saying "False Alarm"

I left my last post to go upstairs to my apartment quickly, to use the bathroom. As I got to the seventh floor, and turned right (I said left, but it's to the right) to go down the hallway, two large ARMED police officers wearing blue shirts and pants, and I think one had a flashlight? came from my hallway and started to get on an elevator as I was getting off. I said, "Um...excuse me...What's going on over here?" and they looked at me and said, "False alarm."

False alarm? There was no noise in the hallway. There are only about 8 doors to knock on, including my own, so I knocked on all of them. No one had heard or seen anything of the police.

What's even stranger, is that this guy, the Asian one who approached me at the subway station, who was funny and asking for my email address, well, he opened the door of an apartment two doors down from mine. I'd never seen him there before and I didn't signify recognition. But it's a little strange. He was having a dinner party or gathering with some people and he made a joke. I didn't meet him close to where I live. I met him in downtown D.C.

So, two weird things: police officers coming out from my hallway and Asian guy from the subway lives right next to me.

And my fucking workshirts are missing and reappearing. Well, not still, but they were.

I went into my apartment and I couldn't tell that anything was different. Nothing noticeable, and my roommate wasn't there either.