That's quite false. It makes no mention of throat-slittings.
The specific text you get when you are seriously wounded by an infiltrator (ie, the worst it can be), is
The attacker cuts through your defenses, and sinks the blade into your body twice before running away, seriously wounding you.
Even if he catches you sleeping, you
always wake up in time to grab a dagger and at least try to defend yourself. Your wounds are body-wounds at worst, not neck-wounds.
And these days, it can even turn out to be not that bad—his blade missed the vital organs, or maybe the blood on your shirt was from a smaller scratch and the major wounds were only in your thigh and shoulder—and you only get a regular wound.
