I do have very high stress tolerance and am more or less incapable of feeling fear - which certainly does affect how I personally perceive things. I am, however, also an empath, or something fairly close to it - that entire sensing how people feel, even if I might not necessarily be able to relate to [i][b]why[/b][/i] they feel like that. 
	But ... yeah. I simply cannot believe it would be possible for me to ever go insane from witnessing something, no matter what it is. (I've admittedly occasionally joked that being mildly deranged is a prerequisite of going into my main field, but that's beside the point.) Protective instincts and inability to feel fear combined, I'd just do something utterly stupid from self-preservation standpoint (and past has proven that I actually [i]will[/i], too). And feel guilt afterwards if I couldn't stop something from happening.
	(In a sense, I'd even say that in some instances, actually seeing things for yourself can bring a sense of closure and peace of mind. With death of someone you cared about especially... Or being there and at least [i]trying[/i] to do something, if something something futile, as opposed to just being somewhere else and not knowing a thing.)