Stupidity: In the freezer you can see the electrical wire power cord that is powering the motor on the wall. She could have easily pulled/ ripped the wire to stop the freezer from working. And when the chemical bomb is in the mixer they could have unplugged the machine which would stop it from going off.
Stupidity: Scream is always considered a parody of the genre; many deaths are grounded in reality, but the one at Jennifer's house it just isn't, since for that to happen the killer needed to know that one of the guests he scared out of the house would have to go inside the kitchen (a different room, further inside) to look at the remaining page, be unaware of the gas and light something to see it, instead of bringing it outside or using a portable flashlight like it happened earlier. None of that was predictable.
