Loss by Five Minutes

From below, distantly falling, I saw the rock. It exemplified the argument I had been having with those climbers for a fateful five minutes. Six thirty in the morning found us on our summit on top of the world for a little while; a small world, mind you, compared to Everest but nevertheless it was ours. We left just as the sun tipped the horizon and as it rose, the shadow of a nearby ridge chased us while we descended the ice chute to the snow ridge that circled the crater below.
"Don't go, I warned. "You are too late".
The ice softened steadily, a thin steady trickling of pebbles dribbled down from those sunlit slopes to where we stood, fresh from the summit and now safe, below the crevasse, rope coiled, the sense of pleasure of standing above the clouds still with us, and an easy walk before us. Why, oh why, hadn't we moved on down?
But no. We knew the mountain, we had been on the summit when the air was cold, and still, and dark, we thought we knew these strangers would listen: twelve, in groups of two and three and ones. We stayed. They paid us no heed. They knew better than us.
I watched the rock, no pebble this, bound as it picked up speed and bounced from side to side. I stood silent, watching, gauging, ready to move as its path became clear. The others scattered. But one, seeing the rock bounce to the left, flew back up over the crevasse and rght along its upper rim. The rock checked in its downward dash, flipped to the right where, for one infinitesimal lifelong instant, it occupied the the same point in space as her head and together they tumbled, she ... head over heels ..., into the crevasse. Where she disappeared.