This logic is 100% contradictory to how every police officer, fire fighter, paramedic, and EMT are trained.
The reason the first responders safety is the #1 priority is because you can't help someone if you are dead or injured. I went through EMT training about a decade ago and they stressed safety on a daily basis, the last thing an accident scene or crime scene needs is more chaos or more injuries because a responder didn't put their own safety first.
It may seem counterproductive for the police to be on the offensive but it makes sense if you think about it, if an officer waits until he is attacked or shot he is no longer able to contain the situation. Once someone attacks or kills a cop they know they are going to prison for life if they are caught and have nothing to lose, making them a huge threat to anyone unfortunate enough to get in their way.