So as I came out from running under one of the canal bridges I was paying more attention to my watch than where I was going. My hand slammed into a metal post with the first finger taking the full impact. Result: instant blood, swelling and pain.
Session over. Hobble home.
Had completed an 8 minutes and was on the second of four 4 minute efforts. However, due to the lack of C runners had run the reps at B minus pace and so was already exhausted and about to pack. So didn't actually miss that much running.
Did hurt though. Still hurts now. Wont do that again in a rush.