Now, no matter what you do, the cops will never show up. Agree to exit the mission and then back out of the Unlockables Section.
Then pause the game and go to your 'Unlockables' section-the game will warn you that this will exit your mission. If you want to go around on a crazed rampage without ever being attacked, just destroy something to activate the mini-game. After you finish the story mode, you can play as Venom Normally as soon as Venom destroys anything you enter a mini-game and the police/military will try to kill you relentlessly.