You are in bed one night, alone in the house, when you hear a noise downstairs. You go to investigate and are confronted with a burglar who threatens you with a knife and makes off with your property.
In his haste to get away, he runs out of the back door into the garden. Whilst attempting to climb over the fence, he slips and impales himself on the fence.
How long, if at all, would it be before you called an ambulance?