When Captain Archer generates a subspace implosion by overloading the reactor, the first explosion occurs at the bow, but engineering and the reactor are in the aft half of the saucer.
When Enterprise disabled the engines of the Yridian ship that is spying on them, the ship slows down which allows Enterprise to capture it. This would not happen in space. A ship would keep moving forward at the same velocity until something stopped it.
After being struck by a powerful spatial anomaly, T'Pol is trapped under what is supposed to be a very heavy piece of the wall that pins her leg so that Archer must save her. Unfortunately, the "heavy" wall bounces three times before settling, clearly showing that it is actually quite light as to not break the actress's leg.
Dr. Phlox left Enterprise for Denobula many years before the future events in this story. But when he returns to treat Archer there is no Medical Officer in evidence and no sign that anyone else is now running the sickbay.
The episode begins with Archer rushing to the bridge to witness the Xindi weapon's destruction of Earth. Later, when T'Pol recounts this part of the story in the future, she mentions that Enterprise was still in the Delphic Expanse when the weapon was deployed. Given the Delphic Expanse is at least seven weeks from Earth at warp 5 (and the Enterprise was stuck at warp 1.7 at this point), it seems impossible that it could have reached Earth in time.
However, it's plausible that Enterprise utilized the same subspace wormholes that the Xindi used to transport the weapon and Enterprise would later use itself later in the season. This explanation may have been intentionally omitted to prevent spoilers for later episodes.
However, it's plausible that Enterprise utilized the same subspace wormholes that the Xindi used to transport the weapon and Enterprise would later use itself later in the season. This explanation may have been intentionally omitted to prevent spoilers for later episodes.