To describe how you feel after a girl explodes in your pre-calc class is a tad tricky. I imagine it's similar to how you feel when any tragedy comes hurtling into your life. You're scared. You're fragile. You flinch. All the time. You may have never even thought about what holds life together. Until, of course, it comes apart.
Same with our bodies. You can imagine cancer and other horrible things wreaking havoc on our doughy shells to, quite literally, disintegrate. So when the unimaginable happens, when the cosmos tears into your very notion of what's possible, it's not that you become jaded; it's that you become unsure. Unsure that you'll ever be sure about anything ever again.