Well, there is a possible script-based rationale for the jump being instantaneous when it isn't supposed to be.
Well, there's a point in the story where the crew's definitely flying blind and really not in control, yeah. A lot of posts are unmanned, so there's a high degree of automation involved (in an earlier draft of the script, Polaris
itself was talked about as an entity with its own intelligence, though never addressed as an individual by the crew. I dropped that idea, but I think one line remains where one officer reports to another, in answer to a question about ship's status, "Sir, the ship doesn't know"). There's a later point in the story where we see that some time passes in the normal universe between the ship leaving a place and appearing elsewhere, which at least suggests that time might pass for them as well.
I don't want dialogue or technical explanations that are more specific than those in Forbidden Planet
or the original Star Trek
(or for that matter and much more recently, Moore's Battlestar Galactica