Piss take

I was in the emergency ward of the local hospital a little while ago. I had been there for about 4 hours and drunk a lot of tea. I called a nurse and asked her where the toilet was.

She said 'What bed are you in?'
'I have no idea'
'Well we need to know that to write it on your urine sample'
'I am not giving a urine sample, I just need a piss'.