Perhaps that is what HE told you he was doing but actually, this is occuring before he steps down from the tug and it is moved into position to be hooked up.
Ok, you mean the random movements before he start moving. It's a very standard practice, with any software featuring animated people, that you *never* have them exactly still at any time, because nobody is ever totally still, and it will look very unnatural so, it's common to have some kind of still pose loop running constantly, with some kind of oscillation around the balancing point.
And of course, since the object is very small on screen, that you don't usually notice small movements from your cockpit eyepoint position, the animation is a *bit* exaggerated, and that is also a very common method with human animations in software products.