When Lars says, "If we stand perfectly still, it won't see us! I saw it in a movie once." He is referring to the 1993 movie, Jurassic Park. In the movie the characters stand perfectly still to avoid being seen by a T Rex.
Due to her resembling Garnet after Ruby and Sapphire first fused, it is likely that Rhodonite's components have not reformed many times, if any, since their first formation.
This is the first and only time Steven heals with his tears instead of his saliva