You're a police captain, relaxing in a local park while on vacation. Parked in front of a deserted lake, your car's motor is running as you gaze into the water. Out of the blue, you spot a killer you once put in jail advancing towards you, a rifle in his hand. Obviously he's escaped, and he's stalked you here for revenge. He's only thirty feet away, and you know him to be a "crack" shot.
You've only seconds to act. (Unfortunately, you left your police gun at home.) He's approaching from your left.
The car dives straight into the water, submerging about thirty feet to the lake's bottom. Water gushes in through the windows, filling up the inside. You're forced to climb out into the water, holding your breath in desperation.
You remove the cap from the nozzle of your tire, inhaling into your lungs the air from inside. You are able to do this for about twenty minutes, hoping the killer will think you have perished and leave. When the air from one tire is depleted, you move to the next and repeat the procedure.
While performing this task, you take intermittent breaks to retrieve the keys from your ignition, and manage to open your trunk. You see inside your bullet-proof vest, and your fisherman's spear-gun.
When you hit the surface you see the killer still ashore, waiting for you to appear. He aims his rifle and you fire the spear-gun, shooting him in the shoulder. He sprawls to the ground, the rifle wrenched from his grasp.
The heavy bullet-proof vest weighs you down, but you finally reach the surface, gasping for breath. The killer fires at you. At first the bullets bounce off your vest, but the assassin is smart. He's also a sharpshooter. So he aims for your head.