Looking at the book, it looks like you have to move straight, but at that point you'd be free to turn either way. Seems odd to me, but that's what the rules say.
I wish to have no connection with any ship that does not sail fast; for I intend to go in harm's way. - Captain John Paul Jones
I think evade should give a +4 bonus to a roll or turn in that direction. Now I know that if I don't want to follow my evade direction I can set max speed and hope for a failure.
Forward with the fail, turn right, forward, turn right, forward, turn right, forward, turn right. SO I should be staring right at the Mustangs 4:00