Almost OHKO'd a firespray with a lucky Adv Torp. Someone knocked off a couple shields, then the torp threw in two Direct Hits to finish it.
If you can roll # of attack dice = hull + shields you can one shot it.
So there are way to one shot a Tie Bomber or Defender.
Technically, you can do it with less. I mean, you could launch the 7-dice attack and pull nothing but Direct Hit crits. It's incredibly unlikely, but remotely possible.
I had a game about a month ago first three crits I pulled were all direct hits and I'd shuffled the deck before the game, same match I rolled eight blanks in one phase losing Vader and having rexler reduced to one hit point, I did something to anger the dice gods.