Continuity mistake: When the Lasers have finished killing everyone, the EMP equipment is next to the glass wall. When Alice walks over and looks in to the corridor, it's moved. (00:32:20)
Continuity mistake: When Kaplan is walking through the corridor to get the EMP and head into the Red Queen's chamber, Medic's legs are together. When we see all the power shutting off, her position has changed and now her legs are apart. (00:32:40 - 00:35:50)
Continuity mistake: When Kaplan tells Alice not to listen to the Queen he is carrying the equipment by his right shoulder. When it cuts it has suddenly moved over to his left shoulder. (00:34:45)
Continuity mistake: When Alice enters the kennel where the zombie dogs belonged to she passes a blue trolley on her left side. When it cuts from inside the room where we watch her through the window walking, she passes the same trolley again. (00:46:05)
Continuity mistake: When Alice escapes the first zombie dog and locks herself in the room, a zombie approaches her and she kicks him down. When the zombie falls you can see his tie is partially outside of his suit. When it cuts to Alice reaching for his gun, the tie is tucked inside his suit. (00:47:20)
Continuity mistake: When the zombie dog jumps through the window Alice makes a run through the metal door and you can see the door is clean. When it cuts there is lots of blood on the door even before the zombie dog jumps on it. (00:47:45)
Continuity mistake: When Matt is at Lisa's desk he looks through some papers, he is looking at a paper which has black squares on it. Then he puts the paper down and looks at another paper. When it cuts to him noticing Lisa approaching he is now holding the paper with the black squares again. (00:50:20)
Continuity mistake: When zombie Lisa lies dead on the floor her hair and the papers she lies on change position between the shots. (00:50:55)
Continuity mistake: When Alice and Matt run to meet up with Spencer, Kaplen, and Rain, Alice screams "Don't shoot!" and Spencer, Matt, and Alice try to close the door from the zombies. A zombie then grabs the inner part of Spencer's arm, then a shot moves showing the zombie holding onto Spencer's arm from the bottom, then back to the inner part. (00:55:45)
Continuity mistake: Near the end, when Alice, Rain and Matt are talking to the "Red Queen" in the virus lab, there is a wall-mounted LG Flatron TFT display where the Red Queen shows surveillance footage, etc. One can see an inventory type barcode label in the bottom centre of the screen. The camera cuts away briefly, and when the camera shows the display again, the barcode label is gone and the LG logo is in its place. (01:14:50)
Continuity mistake: When Spence has been killed we see the broken monitor which has a white column through the screen, which turns black or white depending on the shot. (01:16:00)
Continuity mistake: Near the end of the film, on the train ride out of the Hive, Rain is quite close to becoming undead. When she speaks, we notice her teeth are still "movie-star white". However, a few shots later, when she becomes a zombie, she sort of hisses where you can see it has taken what couldn't have been more than a few mere minutes for her teeth to become brown and discolored. (01:21:00)
Continuity mistake: When Matt gets scratched by the mutated Licker at the end of the film, the scratches on his arm appear before the creature's claws actually hit him. (01:24:15)
Continuity mistake: Shortly after the Licker pulls Kaplan out of the train, Matt shuts the door so it can't get at the rest of them. The Licker goes on the roof to use the back entrance to get into the car. Matt hears this and rushes to bar the back door. Pay attention to the near dead Raine. She suddenly gets a lot more life and quickly moves out of the way to avoid being accidently trampled. (01:24:55)
Continuity mistake: Alice wakes up at the end and is completely nude with the exception of some paper taped to her front. We see when crawls under the bed that this is the case. However as she is cocking the shotgun in the streets the wind blows open to the doctor's jacket she put on earlier, but it also shows that she is now wearing white underwear to hide her modesty in case of a mishap with the wind. (01:30:00)
Continuity mistake: At the start of the film, the scientists are attempting to breach the window with an axe. Later in the same lab in the movie, Alice picks up an axe, even though it was shown before being wielded by the zombie.
Answer: Actually the T-Virus was originally meant as a cure for a genetic disorder that Dr. Ashford and James Marcus daughters suffered from. The reanimation was a side effect and James Marcus was killed by Dr. Alexander Isaacs so he could take control of it and turn it into a bio-weapon.
lionhead