Are you suggesting that you believe wearing a cycle helmet prevents that possibility? If you are, that's rank nonsense, as the thousands of people who die in cycling helmets annually would attest, if they could. Most of the world's cyclists -- by far -- ride without a helmet, and yet they do not die at a greater rate than helmeted cyclists do.
Maybe their decreased cognition is partly why.
Not prevention---mitigation. It's not either/or.