Blooper

The locomotive leaves Philadelphia as a diesel electric. Later, in an overhead-view, the locomotive is electric, with a pantograph and other electrical equipment clearly visible. Later, it changes back to a diesel electric model.

When the train leaves Philadelphia, it has four coaches. In the aerial shot, it has five.

(at around 11 mins) When the students and faculty are leaving the building, a girl in a blue shirt boards a bus. When Elliot and Julian are talking a little while later, the girl in the blue shirt is walking in the background.

At about 42:35 Pvt. Auster holds up a map of the southeast corner of Pennsylvania. Neither Filbert, Harrisburg, or Philadelphia are anywhere near that section of map.

When Julian is in Princeton , his red Jeep goes down the street, not passing any driveways, and comes to a stop. In the next shot, the Jeep is stopped past a driveway on the right.

(at around 50 mins) After leaving Filbert, when everyone splits off into smaller groups in the field, Elliot goes to the truck to find a map. Only the passenger door is open, yet the door ajar alarm is dinging. It's a Ford truck, so the alarm would only ding if the driver's-side door was open.

The weapon the Private draws from his holster is not a M9 Beretta 9mm handgun, standard issue for all conventional Army units, including MPs.

When the news reporter explains the concept of a "preservation switch", the on-screen caption says she is outside the CDC headquarters. The building in the background is actually the United Nations.

Westover Military Base is an Air Force Reserve Base. The Private should be an Airman.

When Jerry is shot by the rifleman in the house, the exit wound to his head is inconsistent with the angle of the entry point. Also, considering the near proximity of the entry point, he would have a large portion of his head blown off.

Everyone left the Filbert diner by car, but the majority came to town from the train that made an unexpected stop. Most of the people at the diner are either locals looking for information, or other visitors who came by car.

(at around 1h 6 mins) During dinner, Mrs. Jones says she grows her own food. The sliced bread on the table is potato bread.

When Mrs. Jones bangs her head on the outside of the exterior wall, a picture frame bounces around as her head thumps the wall. The wall is supposed to be stone, 16-18 inches thick.

When Pvt. Auster is affected by the phenomenon and starts walking backwards, his foot slips but he controls himself to avoid falling. That shouldn't happen with a person who has lost their survival instinct.

(at around 1h 7 mins) After dinner, Ms. Jones tells the group that the guest room is up the stairs and to the left. Given the position of the stairs to the room when Elliot talks to Ms. Jones from the top of the stairs, the room was to the right.

At Ms. Jone's home, she mentions that the guest house was built to house escaped slaves during the Civil War. When the talking tube connecting the house to the guest house is shown close up, the end of the pipe is threaded. Threaded pipes were not in widespread use until long after the Civil War.

Westover Military Base is near Chicopee, MA, over 500 miles from Filbert, PA.

Filbert, PA is a 6-road town near the state's southwestern corner, with no train station or diner.

In Philadelphia, the characters board a train to Harrisburg, which is in south central Pennsylvania. It stops in Filbert soon after. Filbert is south of Pittsburgh, far west of Harrisburg.

The characters board a train to Harrisburg from Amtrak 30th Street Station. Amtrak's Keystone line runs to Harrisburg, but the characters are on a SEPTA train, which does not.

On the train, Julian tells Jess that Mommy has gotten on a bus to the "town of Princeton". Anyone living in the Philadelphia/New Jersey area just calls it Princeton.

Except for one elderly pair of women, who were knitting while watching the news and wearing gas masks, nobody made any arrangements to protect himself or herself. Nobody used any breathing apparatus, nobody used any mask, or full body cover or any personal protective equipment. Even if they were not sure whether it is airborne or water-based or light-based or whatever, they should have made whatever means they have of they could lay their hands on to protect their bodies from coming into contact with the toxin, but nobody at all took any precautionary or preventive steps at all to protect their own bodies.

(at around 58 mins) A man refuses to let Elliot and his companions into his house because he does not want to let the "poison gas" inside. However, all the house's windows are open.