[throws dart at wheel] Gon losing his arm is a representation of [follow-up throw] his severing of his relationship with Killua [nails top of board] instead of his following in Kite’s path. The significance of Killua healing Gon’s arm and then leaving [puts hand over eyes] is that Gon’s journey in the Chimera Ant arc is of fully abandoning Killua without realizing that Killua is his own left hand (or right hand if we go by the loss), and failing to win without Killua to bail him out. Killua getting Nanika to heal him means that Gon’s arm healing is Killua restoring himself to Gon’s side, and then Killua’s departure is him telling Gon to start operating as a whole and complete being without him.