Any weapon that does sufficient damage in one hit to wipe out the physical characteristics will kill with just the first hit. Especially if the target currently has prior injuries from previous combats (new combat, first blood applies again) a Broadsword (4d) or Lasrifle (5d) from book 1 pg 47 could kill right out.
First blood/first hit isn't ignored if the character is already wounded when entering a new fight.
EX) Jimmy Jarhead, IM, (777777) gets into a street fight on Monday. All kinds of edged weapons. Jimmy survives, but his current stats are (473777) after what the medic could do for him that evening.
Next day the poor Jarhead "find" another altercation with some highlanders, who challenge him to a duel with Broadswords (the weapon, not the ship type). While using his cutlass skill that all Marines seem born with he isn't totally defenseless, the very first hit from one of those weapons could easily score enough to kill outright.