What does the Captain refer to when he says "Something has been added"?

Question

After the Captain shoots the leaping tiger, 2 questions emerge.

1. He says to Altair "you really don't know (or similar)" What doesn't she know?
2. The scene eventually switches to the inside view of him approaching the doctor, who has been patiently waiting for Morbius to emerge. He turns and looks back and says to the doctor "something has been added". I don't see what they are both looking at and wonder if a scene has been cut? Does anyone know?

Answer 1

As I interpreted the scene(s)...

Altair has no experience or knowledge of humans or human interaction other than that of herself and Morbius. So, the crew are new to her, and male attention is entirely outside her experience or understanding (at least to that point in the story). The captain understands this and is remarking on her naivete.

The "something added" is the sexual dynamic between Altair and the crew, as well as the tension it creates between Morbius and the crew.

That tension between Morbius and the crew over Altair is what is later manifested by the invisible creature (out of Morbius' subconscious) attacking the ship.