If you witness a crime, you must call the police. Everything else has a chance to end in prison for you already. Do you want to live in the Middle Ages and concepts or in the 21st century and the rule of law?
and----
Formally, you are absolutely right. No one has the right to demand more from you. But in fact it is a question of justified or unjustified risk. The police will be on the spot in 20 minutes. Maybe even 40. Or maybe more. And if you want to live in the 21st century or in the 34th, in a rule of law or on the Alpha Centauri, all this time, sorry, no one will fuck.