Question: How did they climb the grain silo without making noise? Why did the silo door come off its hinges?
Question: Where is the mailbox with the Abbott's name on it?
Question: The daughter already found out about her cochlear implant giving off a frequency that scared the aliens away, so why did she not turn it on when they were in the truck? If she had, Lee would not have had to sacrifice himself.
Question: Why did the dad sacrifice himself when all he had to do was toss a hard object at a metal object to distract the monster?
Question: The father seems to be a very scientific guy. But why hasn't he built some "sound-grenades" which they always carry around and throwing them away to distract the dangerous aliens when they are near? (for example loud toys, egg timers, etc.).
Answer: Possibly because it would be too dangerous. Most times an object like that could not be thrown far enough away to allow the family to escape, particularly in a panicked situation. A creature might be momentarily distracted, but would quickly zero in on them as very frightened children would probably be yelling, screaming, and crying.
Question: Why not live underground most of the time and only emerge when necessary?
Answer: That's essentially what the family is trying to do. They come up for supplies and to use the radio to try and reach the outside world. They built the basement area and used what supplies they had for soundproofing.
Question: Why is water flooding into the basement?
Answer: During the attack on the compound while the baby is being delivered one of the creatures breaks a water pipe and it begins flooding into the basement.
Question: Why can't they just build a trap to hunt the beasts down?
Answer: We see in the family's basement that the father had gradually been learning about the monsters. He may have planned to trap them at some point in the future, but as it stood, he didn't know enough about their weaknesses. The monsters were shown tearing through a truck and a grain silo like tin foil, so any trap that they would use would have to be extremely strong.
Answer: Although it's rather vague, the plot premise is that there are hoards of these creatures that have taken over most of the country, if not the entire planet. Trapping the ones that are in the family's vicinity would have little effect overall and no doubt they'd merely be replaced by other creatures.
Question: Why are they using so many candles/gas lamps when they have electricity, esp in the Monopoly scene?
Answer: Electricity would be a precious commodity, to be saved for essential purposes/emergencies. Why waste it when you have candles/gas lamps, which are far less resource-intensive?
Question: How would a deaf person know whether they're making a noise? Was the daughter constantly monitored, so she didn't inadvertently break a branch, slap her hand on a table, do anything that makes a noise?
Answer: She's deaf but is fully cognizant, educated, and old enough to be aware. Just because she cannot hear anything does not mean she doesn't understand what makes noise and the need to be quiet at all times. She also normally uses a cochlear implant that allows some hearing, but due to the invasion, it is currently unusable.
Question: Where is the electricity coming from? Surely all power plants would be out of commission after more than a year. Gas powered generators would be too noisy and alert the creatures.
Answer: There are shots in the film in which we can see solar panels attached to the roofs of the buildings, so this is where it comes from.
Question: What were the fires for on top of the silos at night?
Answer: The people used it to signal others that they were there. A similar convention has been used in other movies. When the two children were on top of the silo, they noticed the other fires were all gone indicating that the other people out there were no longer alive.
Answer: If there were other survivors, they could see where they are. There was another fire in the distance. Lee saw the other fire and chose to make one of his own. Probably in hopes that the other survivors could come and help them live.
Question: Why don't they just abandon the place and go to somewhere safer?
Question: The father keeps his daughter from going down to the basement. Why?
Chosen answer: The basement is filled with electronics, and if Regan goes down to the basement, there's a risk of potential dire consequences if any accidental sounds occur.
Question: In the beginning, at the abandoned market, the dad gives something to his daughter right before the family leaves the place. What was it and what for?
Chosen answer: Of the things Lee has collected, Regan first picks up an old circuit board that Lee says may help boost their radio signal; then Regan picks up a new package of a Leatherman Skeletool CX, a 7-in-1 multi-tool, which Lee says is for her. It's a handy tool for her to have that includes a knife, pliers, wire cutters (we see her using it later to cut a sound wire in the toy space shuttle), etc.
Answer: He gives her a pair of pliers, but I don't know why he gives them to her. My guess is that they are for her to use when she fixes things.
Question: If they were still uncertain of their safety, why was the baby no longer under oxygen and his box with its lid? Especially when Lee had to leave them alone to look for the other kids.
Question: How do the alien creatures orientate? They're blind but sensitive to noises, so I guess it is supposed to be some kind of echolocation - but first, echolocation is not a way of "seeing" your environments constantly, especially not suitable for running like crazy in a forest full of trees and obstacles. Second, by using echolocation, they should be able to locate moving objects even it's noiseless. So how?
Question: Who is running the power plants so that they can turn the lights on? I work at a power plant and it is not quiet.
Answer: If you look closely at the background in one scene, you can see solar panels attached to the roof of the home, providing them with energy. Additionally, the original script also mentioned that the family also used generators that were located underground so the noise would be muffled, though I don't believe it's mentioned in the film itself.
Question: Where does all the power for monitors and lights come from? I assume power is down, a diesel aggregate would be too loud and hydropower too weak. Solar cells?
Answer: While it's never directly addressed, one can see solar panels on the roof of the farm buildings at several points in the film.
Answer: Because there's no guarantee that would work...the creatures don't just go insane for any sound they hear. They've already discovered there are humans (or at least, something they can kill/eat) within the truck, so just hearing some random noise might not be enough. Instead, he makes it clear to them that he is a human and vulnerable, so they switch their attention to him, knowing that they can get him with less work than it would take to rip the truck apart.