A police officer mistakenly shot at troops taking part in a large-scale Bundeswehr training exercise in the southern German city of Erding, injuring a soldier.
As reported the days before (translated from German):
According to the Bundeswehr, the deployed forces are to train operations against threats behind a fictional front line, in what is referred to as the “rear area.” This includes scenarios involving drones, sabotage, or so-called “irregular forces,” meaning armed fighters not belonging to a state army. The assumption is that a NATO member state is attacked, and the alliance must respond to defend it.
Training will also focus on tasks such as working at crime scenes, directing traffic, locating weapon caches, combating illegal arms trade, and protecting critical infrastructure, for example, at the decommissioned Isar 2 nuclear power plant. Soldiers will also practice defending against enemy drones and deploying their own.
As reported the days before (translated from German):
Ok, and how does that scenario involve having to shoot on clearly marked local police forces?
Local police was involved in the exercise. So the soldier likely mistook the arriving police force as part of the exercise, when they were not.
I suggest waiting for the report of the official investigation.