LX-140 WITH 14,000 BTU AC AND 14,200 BTU HEATER. Yes I know its pricey at $419.89 but when you think what even a portable air-con is going to cost you, this all in one heater / air conditioner / fan and dehumidifier will cover all year round climate control for your grow room. One thing that really makes it stand out is its big capacity dehumidifier (60 pints).
The person should pass out in 6 - 20 seconds. Depending on the person, irreversable brain damage will begin somewhere around 4 to 6 minutes. At 7 minutes, the brain will be dead but the drowning person missed it all as they passed out at 6 - 20 seconds.
But I do worry that they could slip and hit their head and lose consciousness and drown. You can drown very quickly and it's a silent death. When my 4 and 5 year old take a bath, I stay in the bathroom. Most of the time by 6, a child can do it completely on their own. my son will be 4 next month and i let him stay in the tub for about 15 minutes while i wash dishes or something in the next room. but i make sure to talk to him the whole time and occasionally check on him.