The second appearance of the Subterrans.

When I read on the blurb about the robot bird, I assumed that it would look somewhat like a bird. Silly me. It looks more like a tiny plane, except when it flaps its wings. (We won't ask why a powered shiplet needs to flap in the first place.)

"If the Suberrans were doing anything, we would hear them." Well, not if they heard you coming and shut everything down, Steve....

Venus tells Matic that there is a foreign element in Steve's body and that she must perform surgery immediately. (Present tense, not past tense. I played it through again to be sure.) She then says that Steve was shot, the proof being that she retrieved a tiny capsule. Um, wouldn't digging the capsule out have required surgery in itself? Why didn't she complete the surgery then and there, instead of stopping to talk to the Professor about it? And since when do doctors perform delicate surgery with no assistance? Not even a robot nurse!

Why didn't the hospital window break when the robot shot a capsule through it into the bouquet?

Why were the Subterrans instantly quelled by the reprogrammed robot flying overhead? They live underground! All they would have to do is shut the doors and get to work on shooting a missile at the robot.

BTW, the term "Planet 46" sounds like a designation made by Earth's astronavigation people, yet the Subterrans refer to their planet by the same term.

It's annoying the Subterrans called their planet "Planet 46" why not give it a name to fit them like "Subterrania" or something like that

The writers probably didn't want to confuse the kiddies by having two different names. In the episode Triad, the giants call their world Triad, in spite of the fact that someone from Earth had just named it a few weeks before.

It would have been simple enough to toss in a line such as "We call our world _____."