make ur own saw contraption

Well the person will be put in a 6m deep tank of water, with a key at the bottom. The person has to swim to the bottom of the tank and grab the key to unlock the top of the tank to escape. But the catch is that the tank will increase it's temperature by 3 dergrees celcius every second. The starting temperature will be 35 degrees celcius. So the person will either boil to death or live but be scalded (see more)