After the Avents of episode 7, N has no one left except for J, who he lost trust in. Tessa wasn't human the whole time, and uzi and V sacrificed themselves for his safety. N had nothing left to lose he was alone he then smiled but it wasn't a normal smile it was a smile that indicated he had snapped and went insane as he laughed he went more and more insane and as you walk by you see what he has become

N-sanity: hahahahaha! kills a worker drone