I would ask, in your experience with combat related PTSD, what sort of war zone event that caused PTSD could have happened (and triggered PTSD symptoms) shortly before Melissa was murdered by her husband?
See, now that's the hinky part of PTSD. I know people who have had a specific traumatic, identified event, such as being blown up, shot, or lost someone close because they were blown up, shot, etc while beside them. That seems to be the majority. But I've also talked to, and been told by Military medical personnel that it is also possible that it isn't one specific event that causes it, but rather an accumulative series of events where a person is living in a heightened sense of fear for their lives, such as constant shelling, or continual possibility of sniper attacks, etc. In any case, the big things seems to be, that when doctors refer to the 'break' being caused by a similar triggering effect, they are talking about a severe, episodic event that occurs rarely. What most people don't realize, is that 'breaks', where the person is reliving the original event or situation, happen now and then, yes. But the real problem with PTSD isn't the 'episodic break' but the 'emotional break' that occurs with having PTSD. This can be caused by absolutely anything, and results not in a 'reliving' of the episode, but rather a complete loss of emotional control, resulting in rages, hysterical crying, breakdowns etc.
This can be caused by just about anything, I've seen it repeatedly with quite a few people over the past 5 years. It breaks my heart watching a grown man cry because he can't figure out how much change to give the lady behind the counter, because he's too busy telling himself not to panic, and he's safe, not in any danger, and the guy standing behind him in line with the headscarf on is not the guy who tried to shoot him, etc., to be able to think about what coins he needs to make 37 cents!
You will note, that in your quote from the Mayo clinic, it states that the PTSD can be present when things are stressful, OR when something similar to the original event occurs. I think that emphasis is placed in the wrong order, since most PTSD sufferers are in that state due to what they perceive as 'stressful' more often than when they have a similar event. Severe PTSD itself causes the person to perceive just about everything as stressful, even going to the store.