Continuity mistake: When Bond and Domino jump into the water from Palmyra, the Arabs are shooting at them with rifles from the wall. The submarine starts shooting at the top of the wall. But in the second shot of the submarine it is very far in the background - shooting at a point in the wall which is very very far from where Bond and Domino are in the water.
Revealing mistake: In the shot of the US submarine from below, the waves above move too fast and it is clear that they are little ripples on the water above a small model boat.
Chosen answer: Neither is a professional dancer. Having studied dancing some thirty years before does not mean someone has retained the same level of skills. As you mentioned, Connery was in his 50s by that time.
raywest ★