Does anyone hear that knocking?

So I'm just sitting at my desk in my home office, working on my computer, when I hear this knocking. It's a metal sound. Doesn't sound like it's coming from inside. It must be something outside.

I look out the window and I don't see anybody. But there is this large metal container that the construction workers are using to put their equipment in. I hear more knocking. Oh damn, one of them has been locked in the metal box. Now who do I phone to get someone with a key to let the guy out?

As I'm going through the list of possible people to phone I realize that there is no business name or phone number on the metal box. I could phone the office downstairs, our building has 24 hour security, but they do walk around the building sometimes making them hard to find, and they don't have the key. I could phone the police, but they don't have a key. I could phone the fire department, hey, now there are people with some heavy metal busting equipment...

And then I see a construction guy come and open the metal box and let his coworker out. They seem to be joking about it, so I guess no harm was done.

Oh well, it would have been more fun to get the fire department in on this. Bummer.