"You aren't actually trying to move the ship against it's forward inertia, just turning it and flying straight in another direction."
Umm, WHAT?
You kind of need to cancel the velocity from the first vector before/while doing another, otherwise you'll keep going that way. So if you turn around, point straight 'up' and just use the rear engine, you'll end up going diagnally forward.
Come to think of it, that sort of thing might be good to 'fake out' inexperienced pilots.
Phoenix-D