There's a feeling of immortality you have in youth. You just don't see the dangers around you, or, if you do, maybe you're even excited by them.
Besides, I think that when one has been through a boarding school, especially then, you have some resistance, because it was both fine comradeship and a fairly hard training.
It's disturbing at my age to look at a young woman's destructive behaviour and hear the echoes of it, of one's own destructiveness in youth.