Goofs

When Archer and T'Pol steal the pickup truck dashboard lights can be seen before the headlights are turned on.

In many vehicles dash lights come on when unlocked and/or the drivers side door is opened.

At Approximately 14:20 after Archer and T'pol get into the pickup truck, T'pol asks Archer if he has ever driven a vehicle from (2004) in the next shot he answers by saying "I Can pilot a Starship" The clock reads 8:55 on the Dashboard when he says this. The camera briefly switches to T'pol then back to Archer where the Dashboard clock now reads 9:06.

A blood donation clinic would not keep sedatives like methohexital, or any controlled substance, on hand. Mainly because they have no use for them but also to prevent theft and robbery. The only kind of clinics that would use a drug like methohexital would be ones that perform oral/dental surgery and short-stay surgical clinics.

The man who collects people with the eight different blood types for the Xindi to use in the creation of their biological weapon tells Archer and T'Pol that he has delivered people with six of the eight blood groups, and needs only provide an individual with "B-" and "AB+" for the complete set. When the Xindi attempt to deploy the weapon, Archer says to T'Pol that it is pointless for them to do so, as they only have six of the eight blood types. T'Pol replies that, still, they would destroy "75% of the human population." While 6 of 8 is, indeed, 75%, T'Pol is nonetheless mistaken based on the distribution of blood types among the human population. Only 3% of the human population have AB+ blood type, and only 2% of the population have B- blood type. As such, had Archer and T'Pol failed to thwart the Xindi from deploying the weapon, they would have, in fact, eradicated 95% of the human population, not 75% of the population, as T'Pol states. However, It's unlikely T'Pol would know the distribution of blood types, and she was probably stating it as an estimated approximation.

In some scenes between Archer and T'Pol which take place in the stolen truck, the rear-view mirror is noticeably missing. This is a common technique when filming television shows or movies, so the camera and filming crew do not show up in the mirror.

California license plates were visible on most of the cars passing by.

The final shot shows mountains in the background. There are no mountains in or near Detroit, but there are mountains in California where the episode was filmed.

When T'Pol and Captain Archer are transported 150 years into the past on Detroit, there is a skyline in the distance. This is not the Detroit skyline but the Los Angeles skyline. The US Bank Library tower is easy to recognize even when blurred.

When Loomis is dropping off the call girl at the Detroit warehouse, there are palm trees lining the driveway.

Though correct for California, where this was filmed, in Michigan vehicles do not have front license plates. Even though it is possible that all the cars could be registered outside of Michigan, the Detroit Police cars most assuredly would not have been. Though very similar in 2004, Michigan had white letters with a blue background and California had yellow letters with a blue background, these all appear to be the latter.

This is a revealing mistake and an error in geography. At approx. 12:25, when T'Pol and Archer arrive in Detroit 2004, as they begin to walk, the camera racks focus, revealing the blatantly obvious Los Angeles skyline. It should be noted that anyone who is familiar with LA will be able to discern this even before the buildings come into focus.

If the Xindi are capable of time travel, there would be far easier and more effective ways to eliminate humanity by wiping them out in the past. Going back 150 years to the 21st century just to collect blood types to concoct a biological weapon to use back in the 22nd century is nonsense.

Police arrest Loomis but drive off without seizing his car as evidence, as it would be full of the necessary forensic evidence to link him to the abductions.

Archer and T'pol both spent a lot of time on Earth before joining Enterprise. The show makes it clear that transporter technology is in its infancy and is not yet in widespread use. However, in this episode Archer and T'pol go back in time to 2004 and are almost completely mystified by cars. Surely similar vehicles are in use on Earth in their own time given that they don't transport everywhere yet.

Loomis has a stolen box of methohexital but it is misspelled on the box as "mexhohexital".