A fascinating position at local chess event causing big arguments?!

At a local chess tournament in the under 130 ecf section, 1630 Elo there was quite a crowed gathered round the board i had just finished my game in the under 1800 section so popped over to have a look! The position was king v king & 2 knights? the guy had stopped clocks and called arbiter over claiming a draw, his opponent was livid shouting i am two knights up, his opponent stating he could not deliver mate, the arbiter was a strong player over 2100 himself and tried to explain why the position was drawn, steam coming out of the ears the guy was not happy, they called over G.M Mark Hebden to try and explain the intricate side of the position, the guy who had two knights and king suddenly swept his hand knocking over the pieces and stormed out of the playing hall? has anyone else had such a ending causing such a stir if so please post!