Bomb in Bonn

It's cold in Germany's previous capital, Bonn. So I decided to go underground and take the nice clean subway system.

I was trying to figure out how would someone place a bomb without anyone noticing. For one thing, there are many Arabs on this train but that's a German problem, not mine

This train needs more CCTV cameras and that would be my recommendation to the German intelligence after I point to them the radical cell that placed this bomb

For those of you who did not hear about it, it must be because it did not detonate