"How fast are we going?"
"By what measure?"
"I don't know, multiples of c."
"It doesn't work like that. But: fast… and getting faster."
The stars around them were perceptibly moving, crawling at a snail's pace across the viewports towards the stern.
"Shouldn't they be squashing together? Changing color? All of that stuff?"
"You're thinking in terms of Einsteinian space. We're not in that anymore. The universe can't handle the way the Penrose drive breaks the rules, so it kicks us out until we turn it off. Kind of like my mother did when I played my music too loud."