Blooper

After Meg Throws the medical bag into the panic room and Burnham sees it open for the first time the red plastic case that contains the syringe for Sarah is not there, but later it is.

The amount of coke in Sarah's glass changes between shots.

It is clearly raining outside, yet when Burnham is in the house, he is completely dry.

Sarah's coke can in the first dinner at the house repeatedly turns around between shots.

When Burnham and Raoul get locked in the panic room with Sarah, Burnham rolls back the carpet to reveal the safe in the floor. The film cuts to Meg asking Stephen how he's doing. When it cuts back, Burnham rolls up the same carpet again.

When the bad guys are taping a garden hose to the propane tank, it's clear the tank has an O.P.D. type valve because of the triangular handle on the valve. Overfill Prevention Device valves have an added safety feature; they will not release propane without the proper hose fitting attached, which will depress a spring-loaded valve just inside where the fitting screws in. Fittings like what is on the tank end used on gas grills. A simple garden hose would not release the valve. Therefore, when the valve is opened, no gas would have been released.

Even if they had managed to connect the garden hose to the propane tank the gas would just sink to the lowest possible level as it heavier than air. Hence it would just go down the vent, not up.

When Meg lights the gas, one of the robbers is shown with the clothing on his arm burning, with a blue flame. If the clothing were burning, it would be with a yellow flame.

Jared Leto's character hits the elevator call button in order to intercept Meg and Sarah, but for some unexplained reason the elevator continues descending right past him without stopping.

Meg Altman breaks the mirror with the sledgehammer then walks over the razor sharp shattered glass with her bare feet. But right as she's about to walk out the door you see she's wearing some kind of 'hidden' protection on the bottom of her feet.

When the Altmans are signaling SOS through the vent, Sarah is clicking the on/off switch on the flashlight. It clicks once and the light flashes, but all flashlights have a toggle switch - click for on & click for off. The button should click twice each time it flashes.

Burnham seems to know the security system installed in the house quite well. In one scene he turns of the security system for a specific zone in the building. Yet he doesn't know that the can use the same panel to talk to the persons within the panic room, which is a feature later used by Meg when her daughter is in the panic room with the two remaining criminals.

It is unclear why the intruders didn't destroy the security cameras as soon as Meg and Sarah locked themselves in the panic room, both to mask their identities in case the women were ever able to describe them to police, and prevent the women from tracing their movements (as becomes germane to the plot). Even in the very beginning, before the men screwed shut the doors, the women could have seen all the men grouped two floors down in the kitchen and taken the opportunity to escape through a fire escape upstairs.

Near the end of the movie the two thieves choose to leave the house by going down the stairs rather than leaving via the roof, which would have been a much safer option. That was the way they first entered the house.

The robbers are attempting to steal money and bearer bonds from a safe in the panic room, but any valuables of the previous owner would have been removed before the new occupants were allowed to move in.

When Meg starts searching for a "chocolate bar" once Sarah's sugar level drops, Sarah says she had already searched in the box and had found nothing. Yet we clearly see standard U.S. Military M.R.E. (meal ready to eat) packages which include a high sugar ration (in the form of, or in addition to, a dessert with the meal itself and sugar to be used with the included instant coffee), when Sarah was first searching.

It is incorrectly regarded as a character error that when Sarah's blood sugar dropped too low, she was given an injection of insulin, or, as an edit states, glucose. The label on the syringe and vial combination in the orange case that Meg retrieves from Sarah's room clearly states that the injection contains Glucagon, which is commonly given to diabetics when their blood sugar is dangerously low. Sarah was not given insulin or glucose.

Junior says that Meg had closed escrow. New York does not have an escrow system. Closing on a house is done with attorneys, with a set closing date.

When the E.S.U. (Emergency Service Unit) team enters the house and clears the bottom floor officer Keeney calls for a "bus" or ambulance to help Stephen. When E.S.U. are called to a scene an ambulance is automatically dispatched with them, there would be no need for Officer Keeney to call.

Sarah Altmans blood sugar level is falling rapidly, too fast. But on very low level they want to inject insulin. A big mistake, because insulin is lowering the blood sugar level even more. So in reality you inject it after eating something to avoid high blood sugar level.

Edit: But maybe they don't want to inject insulin, but Glucose. It is not clear in the movie. A Glucose injection would make sense.