After the Alphans rescue Pasc and Etrec and bring them to Medical, Dr. Russell records a status report in which she says that it is 640 days since the Moon has left the Earth's orbit. However, in previous episodes, she has given a figure much larger. For example, in "The Rules of Luton", which was filmed concurrent with this, it has been 892 days since they left Earth. Likewise, The Taybor, which was filmed before this, says it has been 783 days.
Pasc's mark disappears from the point he is seen on a monitor talking to Alpha from the Eagle and doesn't reappear. There's no comment on it from that point forward. [The mark shows that he suffers from a disease that causes its sufferers to kill others. As he shares scenes with Doctor Russel, the head of the medical section, she should have questioned the change.]
While Pasc is holding Helena in the Eagle, Tony orders Eagle One to launch and stand by, hovering above the launch pad where Pasc is present. Eagle One, however, is currently occupied by Koenig and Maya.
It is not explained as to how the aliens' stasis chamber, power unit, and monitor/transmitter had become completely embedded in moonrock.
When sitting in an Eagle, the pilots are capable of achieving visual contact with Alpha through the video monitors facing their seats. But in this episode (as well as several others), Alan and Tony are observing Koenig and Maya on the big screen by a side view of the ship's pilot section, which wouldn't be possible.
The Archanons had established a base on the moon in the past, so they're obviously familiar with Earth's location. But at the conclusion, Mourna fails to offer to take the Alphans to it, or at least to a habitable planet, and the Alphans never ask (similarly, on The Exiles (1976), Tony and Helena fail to ask Mirella for a place to live on her planet for Alpha's personnel).
While Pasc is holding Helena in the Eagle, Helena tells Tony to get a hold of Raul. When Tony switches his screen to the Medical Center, Raul is already staring at the screen.
It was illogical for the Alphans to allow the aliens to roam unescorted through the base. Then when they decide to have Security conduct a search, they fail to use video surveillance (previous episodes have shown that security cameras are set up throughout the base).
It seems that Alan Carter is given misplaced duties on this episode; first having him mine for dylenide crystals, then Tony sending for him instead of an engineer or an electronics expert to take a look at the alien device in Tech Lab 3.