Hospitals which experience surges of unexpected trauma victims publish post-event write ups. I've read a couple on the web. They basically go to triage, training and practice.

Your german hospitals will all be thinking about this, all the time. Any construction site in a german city is only one mis-placed digger bucket away from an unexploded wartime 4000kg blockbuster bomb event.

https://en.wikipedia.org/wiki/Mass-casualty_incident

Just google "mass casualty incident" -They think about this. You will be looked after as best you can, because its planned for.