I can’t say what the ratio should be...How do you know what that ratio should be?
You say cops should not be a “situation”, not sure what that means but for many of them responding to crimes is exactly what their job entails.
In other words As it relates to your ratio, is is possible a police office is 10 times more likely to encounter a murder/violent criminal in the act than a citizen? I don’t know, but that seems reasonable and probably jacks up to 100:1 to intervening to stop a crime.
I’m really not one to ask, I’ve been on all sides of it: I’ve been arrested (multiple times, including for the victimless crime of possession of marijuana); I’ve been the victim of an armed kidnapping; I’ve represented criminal defendants as an attorney. I can certainly say even being the victim of an armed kidnapping I felt more victimized more by the detective after the fact Than by the kidnapper, I can also add I felt more victimized by the insurance company of the gas station I was kidnapped from and their attorneys than either the kidnapper and detective (they literally destroyed the video of the crimes against me, falsely tried to cover up their destruction of the video claiming it never existed, claimed I falsely alleged the crimes and paid they same detective to testify the crimes happened to me across the Street from the gas station).