Factual error: When the first robot is trapped in the lift, the teenagers shoot the propane tanks on top of the lift in order to get them to catch fire and explode, killing the robot. However the teens are firing pistols or shotguns, and these do not contain incendiary ammunition, which is what is required to make the propane to catch fire.
Factual error: Petrol cans sold in shops are always empty. They would never contain petrol when bought. There would be nowhere in a shopping center to get petrol exactly for health and safety reasons.