It's unlikely that electrons would even go through the guy's urine anyways. Once the circuit is shorted, the electrons are going to move along the path of least resistance in the most efficient way possible. Making such a huge trip is neither efficient or the path of least resistance. Urinating on an electric fence is a different story...
but the current had to go throug, otherwise he wouldn't felt anything. if he was in the bad luck, that the urine didn't conduct between phase and neutral/earth, then he got the whole shock throug its urine, since it would be the only way to go.
but anyway. all i want to explain is, that without
voltage there is
no amperage. therefore the voltage (as well the resistor) is the only and one relevant factor (beside of the max. outputpower of the main supply, which will limit the current anyway somewhere in the higher ampere range).