Sentry removal is best done with a completely different knifing technique, and there are a whole shitload of variaties, than cutting their throat. Only if you are a fool, you will slit someone's throat and leave a *small* hole as you described it.
If you're not much better, you'd cut their throat ear from ear.
I'm guessing you're not a 1LT in the USMC. They teach you how to kill someone differently there with a knife; if you can tell me, I'll retract my comment, helpfully put in italics.
I think I might know you from somewheres else as well... say the SC/Forums? Aye, that seems 'bout right to me, Olemiss.
The world in which you live is an interesting one, if that kind of a sound is audible from that far away.hear it half a mile away.