"As it turns out there is a camera nearby that may be picking up the death of the guard somehow."
Yes cameras spot corpses too. Be weary of that. That was an early feature of the mod and in combination with the latest AI improvements may be a little overkill. If I return to the mod I think I'll create a new type of camera exclusive to high security areas and have this new type detect bodies too and set the vanilla cameras back to spotting alive threats only.
*realizes his tea has gone cold *
"As it turns out there is a camera nearby that may be picking up the death of the guard somehow. If that is the case, would that cause a guard some 20-30M away to run for the alarm?"
It appears this new alarm-triggering code has exposed/made obvious a flaw in the vanilla code: it only checked if nearby alarm units were already sounding an alarm, not alarms sounded by cameras (or red lasers). A flaw that would have been hard to spot vanilla as AI rarely went for alarms (they only went for alarms if health was less than a certain value and various other conditions were met). Perhaps I'll fix it, but more alarms sounding is always a good thing as each individual alarm does have limited range, so I'm not sure if I should bother.