Many Cops dont like to risk their pension just to save others.I'll never forget watching the video (not fatso-moore's, but other videos) of the cops outside Columbine school, all huddled around the outside listening to gunshots from within as students were methodically murdered.
Waiting for cops to protect you is a sure path to an early grave.
Or are others have put it,
"When seconds count, the police are only minutes away!"