Maybe start here: "one of the big parts of military training is breaking the reservation of taking a human life"
"erm... no. that isn't a part of military training."
Yes, it is. Considerable thought, research, and effort have gone into exactly that. So: awareness?
I am well aware of what is taught in boot for the USAF, USA and USMC
after basic, for the
combat arms in the USA and USAF, I have to agree: considerable research has gone into breaking the reservation of taking a human life. They actually use the previous Basic/Boot training where they want you to react quickly and go from there.
However, in Basic/Boot (circa 1980-2000), you only get:
Army - one day (maybe two, depending) of hand-to-hand combat, one day of grenade, a week on the rifle range (not all of it shooting) and maybe one day on Claymore or shoulder fired missiles - just enough to make you a threat to everyone around you. It's essentially a familiarization course that comes together in the FTX at the end of Boot.
USAF - you don't get near as much range time, and you only shot paper targets with multiple sizes at about 25 or so meters. I don't think we spent a week total.
Marines - they're a different beast altogether. They begin the induction right off the bat and drive the point home, so they do "break the reservation" immediately, which is one reason it is one of the longest induction training courses of the military (I believe it is the longest, but I've not checked in years)
The Navy and CG are the only two that I don't have direct experience with so I can't comment. I don't expect boot has changed that much in the ensuing decades. It was essentially the same before I went in as my father was a Drill.
So when you talk about breaking the reservation, you really need to include what branch you're talking about, whether they're enlisted or officers (like the USAF) and if they're combat arms for certain branches (sometimes the LEO schools are considered part of the combat arms training)