Early in the episode, Nog's station on the bridge is on the port side. Later, he has moved to a station on the starboard side without explanation. If the Valiant's bridge is laid out the same as the Defiant, he would have started at the chief medical officer's station and moved to the communications officer's station. Even if the bridge layout is different, his position should remain consistent.
Cadet Collins was given a battlefield promotion to the rank of Acting Chief Petty Officer. Petty officers are non-commissioned servicemen, like Chief O'Brien. What distinguished them from commissioned officers is that they enlisted into service without attending the officer's academy. As she is a cadet in the academy, and all other cadets were given commissioned ranks, it is not appropriate that she was made a petty officer.
As can be seen from the unit crest, the cadets belong to the "Red Squadron". It is incorrect to state that they are "Red Squad" as that is a different type of organization. A squad (or flight for the USAF) is comprised of about 10-12 individuals. Multiple squads are in a platoon (or a squadron for the USAF).
In the opening battle sequence aboard the runabout, several camera moves (in particular the sweep where the camera banks sharply to reflect the motion of the runabout) inadvertently disclose the fact that the forward windows have been removed to make filming the scene possible; in the most visible example, a sizable hole can be seen in the center of the piloting console, where the ceiling support strut between the windows usually was.
In the establishing shot of the runabout outside the starbase, the runabout is scaled much too large in comparison to the base. The runabout would have to be as large as a full size starship (hundreds of meters long) to appear that large, when it is only meant to be 23 meters.
While the USS Defiant model was altered to represent the Valiant in all shots newly created for this episode, some stock shots of the Defiant at warp were reused and the Defiant's registry number, NX-74205, can be briefly seen on the ship's hull, rather than the Valiant's registry, NCC-74210. Some of the same stock shots are used multiple times, making the error even easier to pick out.
Nog tells Jake that everyone on the bridge has died and so the two of them must proceed to escape pods, yet he never checks a single person to confirm that they are dead--he simply gives a quick glance around the room.
The Jem'Hadar battle cruiser destroys all the escape pods from the Valiant except for the one carrying Jake, Nog, and Collins. The escape pod is picked up by the Defiant after transmitting a distress signal from within Dominion space. The Jem'Hadar should have easily been able to identify and destroy that escape pod as well.
The runabout only travels away from the starbase at warp for a few minutes before it is destroyed by the Jem'Hadar, and is only capable of moving at warp 5. That's not nearly enough time to put them deep into Dominion held territory.
The same supporting crewmen are seen preforming vastly different functions throughout. Cadet Collins is both the transporter chief and apparently takes shifts in sickbay. Cadet Shepard is both the helmsman and is seen working security when apprehending Jake. While this could be an indication of how haphazardly the Valiant is being run, even a poor captain like Watters should understand the importance of structure and stability for his crewmen.
Acting-captain Waters orders cadet Collins to escort Jake to sickbay. He makes no mention of treating his wounds personally. The ship would need to have a dedicated medical staff, yet Collins is shown treating Jake's wounds herself.
Watters claims a battlefield commission, but his story later is that he took over when the actual commissioned officers were all killed. The death of a superior officer would only place him in command until a commissioned officer would arrive. As such, Nog, being commissioned already, should automatically become the ship's captain upon his arrival.
When Nog is promoted to chief engineer on board the Valiant, he is given the rank of Lieutenant Commander. However, throughout the rest of the episode, he is seen with only two pips (one full pip and one "hollow" pip) signifying the rank of Lieutenant Junior Grade.
Cadet Collins refers to the Valiant as a "state of the art warship" and is not corrected. Defiant-class ships are officially designated as escort vessels, as Starfleet does not build warships.