From the top view of school assembly hall where all students are gathered, Martha is already sitting between Bartosz and Jonas. In the next scene, she comes and sits herself between them.
Jonas' medication comes in a typical American orange pill bottle, which don't exist in Germany.
Jonas uses US orange pill bottles for his prescribed medicine in the first season even though German pharmacies only hand out pills in blisters and paper boxes.
From S1E2: Ulrich suspects the door in the cave might lead into the nuclear power plant but he has no way to know. The cave does not appear to be on anyone's particular property. As a police officer, he could easily have ordered contractors to break the door down from the cave side, say with flame torch.
Both being police officers, they would never have disturbed the site before forensics did their research. Ulrich being a parent first, might not have followed the right protocol, but he would have been stopped by his partner.