index futures aren´t that dangerous, compared to commodities
they have circuit breakers and limit down even in pre/market. Moves of over 1000 DOW points and 100 S_P points don´t happen, not even with 9-11
only in case of like UFO´s suddenly landing, or dollar going from 1.50 to like 6
yes you can lose more than you have in your account, thats why you trade only intraday, and only with stops, and only with the brokers phone number next to your desk.
preferably you have $5000 in a second brokerage account you can use for hedging in a most extreme scenario.