What's the alternative to test the thing practically? Getting people to opt in before they got stabbed or shot or whatever would be phenomenally difficult - mak

What's the alternative to test the thing practically? Getting people to opt in before they got stabbed or shot or whatever would be phenomenally difficult - making contact with that demographic - and could delay the study by years or decades. And in the mean time more people would possibly be dying, something they haven't consented to either.