Panic Room
In 2002's Panic Room, the intruders flood the panic room with propane, but Jody Foster's character uses a lighter to ignite the propane, causing it to burn along the ceiling. Realistically, this would have been impossible, since propane is heavier than air.
Halloween
Halloween is set in the fictional town of Haddonfield, Illinois. Despite this, in some scenes, you can see palm trees in the background! What kind of midwestern small town has the terrain to accommodate palm trees?