To safely and easily kill cops, go to the apartment and walk straight to the window. Enable a "Weapon" code to get the sniper rifle or rocket launcher, then shoot cops and people from there.
Enable the "Drive on water" code and the slowest car possible. Then, get the highest wanted level you can. When the cops are on your tail, find the ocean and, if they are directly behind you, jump into the ocean while in your vehicle. The police will follow you into the water and drown.