Firstly, ensure that you have back-up. Make sure Sweden is with you so he can offer suppressive fire if necessary.

Secondly, obtain some sort of device- preferably a long stick or a mine sweeper's line- to tip the box over from a safe distance.

After that, it depends on what you have uncovered. I am certain you can use your discretion to come up with a suitable plan of action.

That is all!

Germany, you're so cool!

Well, I heard he was an expert on handling mysterious boxes, haha.

haaaaa~ I don't know what you mean!

...in a manner of speaking, yes. Though that was more of a crate. Perhaps you should poke it a few times and see if you get a response?

But don't scare it!

To the contrary! A demoralized opponent is one unable to offer resistance! Use such means if necessary!