When Sho is approaching the "rescue pod" and the breach happens Miranda and David are having a hard time not to get sucked out into outer space. Yet at the end of the scene they effortlessly float back into the main part of the space station.
Right after Rory tells Hugh 'you are gonna be a father', Hugh leans back and his hands are NOT inside the gloves he is using to get Calvin to react.
In early scenes, Sho's wedding band is very thin. When he is trapped in the sleeping pod, it is noticeably wider and thicker.
Capturing an object in space is a delicate, highly controlled, very precise set of maneuvers. At the beginning, the crew captures the "capsule" ejected from Mars at a velocity that would have easily destroyed the capture arm and anything connected to it.
In the opening scene, the view of outer space from the International Space Station shows twinkling stars. Stars do not actually twinkle in the way we see them, but the twinkling is an optical illusion of the light from stars being refracted by the earth's atmosphere.
When the station is opened to space, air starts rushing past the protagonists at high speed, random junk flying by with it. This goes on and on, while they spend a lot of time struggling to save Sho. In reality, the wind would die down quickly and they would be in a severely depressurized atmosphere in a very short time, causing almost immediate loss of consciousness for anyone not holding their breath (which they clearly aren't).
When they are attempting to revive Hugh, they get a pulse back and someone says, "we have a pulse. Sinus brady, 98bpm." Brady is short for bradycardia which always indicates a heart rate of <60bpm (beats per minute). So if his bpm is 98, it would not be sinus brady, it would be Normal sinus rhythm.
As demonstrated by the fires on Apollo 1 and the Mir space stations, open flames are so dangerous they would NEVER be used inside the space station - for any reason.
The movie shows "Calvin" being attracted to and consuming oxygen from the lures they used to get it to the lifeboat as well as stating many times that since it is carbon-based, it needs it the way humans do. "Calvin" is from Mars where the atmosphere is 98% carbon dioxide. While there wouldn't be enough oxygen on modern Mars for the survival of the creature, it's explained throughout the film that it had been hibernating for possibly millions of years, since a period in which Mars had higher oxygen levels.
The crew attempts to kill Calvin by venting all oxygen to space. While the creature does survive for a few minutes outside the ship, it's explained that it needs oxygen for longer periods and would have eventually died outside the station.
Rory tries to kill "Calvin" with a handheld flamethrower. In a micro-gravity environment such as the International Space Station, and without any sort of anchor or tether having been attached, each time he fires a burst, Rory should be thrust backward, directly opposite his weapon's aim.
Despite moderate quantities of blood floating around following deaths, none of it splashes onto surfaces.
When in the communal area (while Sho is watching his wife giving birth), various objects handled by the characters do not behave as though in a zero gravity environment - Ekaterina sets a photograph on the table, and the pages in David's book do not float.
Early in the film Dr. Jordan (Gyllenhaal) is depicted floating weightlessly through the space station carrying his electronic tablet/device in his hand. At one point, when he sets his tablet down on a nearby workstation, the way the corner of his tablet drops from his hand reveals that he is obviously in a gravity environment where the tablet actually has weight.
When David takes manual control of the life boat to steer it towards deep space, the display already shows the trajectory for the override before he touches the joystick.
When the photograph comes out of the Polaroid camera, it droops downward. This wouldn't happen with zero gravity, since there is no force to cause the paper to fall down.
In the onscreen end credits, Formosa Group is credited twice in the same function of Sound Editorial Services. Both credits are on the same credits card.
The pod in which the Calvin is entrapped has the oxygen vented from it so that it is a vacuum inside the module. Assuming Sho Murakami could even have opened the door, the explosive force of the oxygen entering the module should have blasted him across the room and either killed him or severely injured him when he struck the other end of the module.
Given the concern about firewalls, it's unlike the CO2 system would 1) have outlets that needed to be closed one at a time, and 2) be interconnected to the main space station. Also, if it was properly designed, the 'ports' should have been operated as one unit, all opening or closing at once.
Given the concerns about isolating the lab from the main space station, it's probable that they would have protocols in place that specifically required them to leave injured or "contaminated" astronauts in the lab in case of containment breaches. There was, but Rory (Ryan Reynolds) broke it to get Hugh (Ariyon Bakare) out. Thats why Rory was left to die inside instead - he had said he was more 'disposable'.
Officials back on earth are obviously very concerned about aliens returning to earth and would have procedures in place to destroy the lifeboats before they landed.
If the testing lab was really quarantined it's fireproof vents shouldn't be connected to the rest of the ship. The water/gas supply could've been stored in a tank in the same compartment. Poor preparation of the supposed "firewalls" on Miranda's (Miranda North) part.