The (simulated) urine in that video can be clearly seen falling in drops, with air gaps between them, and not as a solid stream.
In my youth, I observed many drunks urinating* on
LUL▸ tracks.
AFAIK▸ they all survived.
The voltage to earth is a bit less than on main line
DC▸ electrified routes but still dangerous, about 440 volts to earth on LUL rather than 750 volts to earth on network rail. Both voltages vary.
Please do not try it though, just in case.
*At Wood Green underground station, when the Great British Beer Festival was held nearby, at Alexandra Palace, about 1978. half a lifetime ago, but I doubt that urine or electrified railways have changed much since then.