Factual error
Propane is heavier than air. When blown in from the house, it will sink to the floor instead of staying near the ceiling.
Although it is rare for 911 operators in New York to ask the caller to hold the phone, if the caller loses contact, they usually send a patrol car over quickly.
When the SWAT team (Flying Tigers) arrived in the house, Commander Kenny was calling for a "bus" or an ambulance. However, when the Flying Tigers were in action, they would have come with an ambulance. Therefore, this call was completely unnecessary.
Coherence:
During Sarah's first dinner in the house, the position of the coke bottle and the amount of coke changed during the camera switch.
It was obviously raining outside, but when Burnham entered the house, he was dry from head to toe.
In order to reach a safe place, Burnham rolled the carpet twice in the film.
When Burnham saw Meg throw the opened medicine box into the Shock Room, there was no red item containing the syringe used by Sarah, but there was already such a thing in the medicine box later.
When Meg taped the vent, she left the bottom of the vent not completely sealed. But when her camera showed that she went to the second vent to apply tape, the first port became completely sealed.
Props or staff wear help
When Meg turned on the TV for the first time in the Shock Room, you could see the shadows of the crew members moving in the upper right corner of the screen.
Meg Atman smashed the mirror with a sledgehammer, and then walked straight through the sharp pieces with his bare feet, wearing some kind of "invisible" protection on the soles of his feet.
