Because that's what I did 
He was weeing shielded by his own van, hidden from sight of the road. But not from my front door sadly.
I realise that he must have been caught short with few options, but a few more feet down the road would have given him bushes to spare his blushes.
And WHY THE CHUFF did I feel the need to splutter 'oh I'm so sorry, excuse me, I'll go back in...there.... sorry
'