Looking at it again, yeah, it looks more like a charter. So it's probably that (unless this is something specific to Germany) it doesn't have an escape aid (hammer).

I know the UK and Germany are different, but when I went to a DoDEA school in the UK, our busses were not the same as the other school busses / busses used in the area. It was many moons ago, but we had a charter bus for high school. But neither our middle school nor high school bus had a little hammer to use, just emergency doors.

I’m assuming theirs didn’t either it they may not have known.