Corrected entry: When all three men are together, writing notes to Foster they are all downstairs, you can see the front door in the background. Instead of carrying on with the conversation she could've just run to the bedroom and called 911 on her cell or the home phone.
Question: Why would 911 put them on hold?
It does happen in real life, and it is sadly a common occurrence in big cities. Living in Los Angeles, I've had to dial 911 a few times. I was on hold for 5 minutes once, and I've read articles about people who have been on hold for way longer. With this film being set in New York city, this did not surprise me. Even Meg and Sarah don't seem too surprised by it, and they opt to call Sarah's father instead.
Answer: There could be a serious major event happening nearby where all the resources needed to be sent ASAP. The 911 operator had to prioritize and assumed the current caller's emergency - whatever it was - was less urgent. There could have been a shortage of operators for whatever reason.
Corrected entry: In one scene, one of the intruders gets his hand caught in the door of the panic room as it slams shut. However, it is shown earlier in the film that the panic room door is equipped with motion sensors to avoid just such an accident.
Correction: The real estate guy put his hand in the center of the whole area so the sensors picked it up - Raul's hand was on the edge of the door so it would not be as easy for the general sensor to reach that exact spot.
Correction: The sensors are spaced quite widely - they'll stop the door slamming on a large blockage, but not a small one, like a hand.
The chap showing them the panic room in the earlier scenes demonstrated the effect of the motion sensor using his hand. Why wouldn't a hand stop it later?
When we see the guy at the beginning demonstrate it with his hand, we see the laser cross his hand, roughly at shoulder level. He then states that there is another one at ankle level. There are only two safety sensors, and Raul's hand, being roughly at knee level, does not trigger either one of them.
Hands/fingers (especially a child's) were probably most likely to be injured before the introduction of sensors; it wouldn't make sense to install a sensor incapable of sensing hands/fingers or small objects. Even a section of clothing (e.g, shirt arm) would be picked up. My garage door's sensor is sensitive to a small leaf, one black oil sunflower seed, and a bug (to name a few).
Question: I don't really understand why Jodie Foster's character didn't tell the police something was wrong when they came to the door. I know she was worried for her daughter but the robbers couldn't overhear and she could have asked the police to come back later, giving her a chance to smash the cameras. Also, considering that she emphatically denied there was anything wrong, why did the police return later with all the guns etc?
Answer: But if Jodie Foster was so keen to placate the burglars and protect her daughter's life then why did she smash the cameras after the police left? It doesn't make sense.
She smashed the cameras, so the thieves in the Panic Room couldn't see what she was doing. That's why the thieves had said, "Why didn't we do that?"
Answer: The cop told Jodie "if you can give me some kind of signal." Jodie runs her fingers through her hair, that's the signal.
Answer: One doesn't ask the cops to come back later, especially when one's daughter's life is a stake. Also, the cops came back because they just didn't believe her and felt that something was up (call it intuition).
Not only that, Jodie Foster said that "they were good", why would she say that they are good if not that they were right?
Question: Why did they keep holding signs up to the camera? Burnham's company builds the rooms and security systems, wouldn't he have known he can speak to them using one of the security panels like Meg does later in the film?
Answer: Meg was using the P.A. from inside the panic room and it only works one way; everywhere else would have a room-to-room intercom system. If there was another P.A. system working the other way, it would have been too loud, as the cop mentioned when he spoke to Meg at the front door. The neighbors heard Meg broadcasting on it. Burnham would know that it would draw unwanted attention and, if heard, could be incriminating.
Cop didn't say anything to Meg about neighbors hearing her on the PA. They were only there cause the husband called the cops after she was disconnected from him.
The cops said to Meg that neighbors called in about a loud disturbance, so they did hear the PA system. Meg covered those tracks by saying it was the TV.
There are two possible reasons that I can think of 1) Burnham probably simply forgot that he could do it, the same as none of them thought to smash the cameras until Raoul saw Meg doing it. They were under a lot of pressure as the plan had changed so it probably just slipped his mind. 2) Burnham knew he could do it but didn't want the other two to know. The other two seemed like loose cannons and Burnham seemed to be the only one who didn't want to hurt anyone. He might have been worried that they'd use the intercom to send threats or something.
It was a one-way PA system, as mentioned by the original answer.
No, it's not. After the burglars get into the room with Meg's daughter, Meg uses the intercom in the bedroom to talk to Burnham who is inside the room. This indicates that it is very much an intercom and not a one-way PA system.
Corrected entry: When they are going to gas the girls with propane they get a garden hose to hook it up. When they do so they stick one metal end into the duct and the other over the valve to the tank. Why does Dwight Yoakam cut the hose in half with a knife? Wouldn't this just let the gas leak into the room that they are in?
Correction: He cuts the hose in half, and then puts the new end onto the propane tank.
The end of the hose doesn't have the same thread as the propane tank. So, he just cut the hose and shoved it over the propane thread and duct taped it to seal it the best he could.
Corrected entry: The portrayal of Sarah's type-1 diabetes is loaded with inaccuracies. We saw her eating pizza the previous evening and along with this any sensible diabetic would have injected herself with enough insulin to last through the night, to cope with the sugars in the food she'd eaten. But in the panic room just a few hours later, she apparently needs another dose - wrong. If her condition was due to stress, she would have needed sugar or a glycogen injection, not insulin. In response Meg searches for sugary food to give Sarah. That's correct, but next thing Meg wants to inject Sarah with insulin, which would kill any diabetic in such a state. Finally, when becoming hypoglycemic Sarah thrashes about, apparently having an epileptic fit instead of what would really happen - she would just become very sleepy, lose consciousness and go into a coma. All this demonizes diabetes into a convenient scary plot device but in reality the condition is quite mundane - typical Hollywood.
Correction: They don't mention Insulin. In fact it is the Glucagon that they inject her with in the end. The symptoms of severe low blood sugar are seizure, which Sarah obviously had, loss of consciousness, stroke and possible death. As for injecting enough insulin to make up for the sugary foods she ate, what did she eat? Pizza? Any sensible diabetic would know the limitations on their starch intake. As a Nurse, I found it to be a pretty accurate portrayal.
As a nurse, you should also know that consuming anything in the MRE would have brought her sugar level up. All carbohydrates are, or convert to sugar. Even protein would have helped.
Correction: At this point, she could not be sure there were only three men in the house. She was unfamilar with the surveillance system, as well as being scared and confused, so it makes sense that she was not thinking clearly.
Twotall
While the facts in this correction are accurate, Meg eventually left the room to grab her phone without still knowing if more than three men were actually in the house, so this correction is a bit iffy.