Well, the Tantive IV was caught in the SD's tractor beam in ANH. That's how the Empire commandeered and boarded the ship. And I would think that if you tried to engage your hyperdrive while in a tractor beam, your ship would likely get ripped to pieces. Either that, or it would be like slamming on the accellerator while your wheels are locked - you're just gonna burn out the engine.

And no, I can't rationalize the Falcon flying right up next to the Executor. They're being chased by all of three TIE Fighters. Maybe if it were double or triple that, maybe they'd have a harder time maneuvering away, but they easily could've altered trajectory away from it as soon as they saw the SSD. So, maybe adding more TIEs into the pursuit would ease anyone's problems with this, but frankly, it's never come to mind. I'm just so caught up in the momentum and suspense, anyway.

-NJM