yes yes we all see how jayce has to follow the steps of viktor's journey, to climb all the way up from the lowest bottom (zaun) to the highest top (piiltover) with a damaged leg...
but why is his leg damaged? it is not the fall down that leads to the fracture. no. it's his hammer.
jayce's leg is crushed by his own hammer. the same hammer he used as a weapon, betraying his and viktor's original hextech dream of progress, hope and prosperity, for zaun and piltover both. the same hammer he used to kill a zaunite child. the same hammer, the symbol of jayce's choice: confrontation over progress, council chamber over a science lab, everyone else's expectations over viktor, golden boy over partner. the same hammer, a promise broken.
it's the consequence of his own actions that damages jayce's leg.
his hammer - with everything it symbolizes - crushes him. so later we see jayce dismantle it to brace his leg.
jayce lets the past go with all it's mistakes, leaves it behind and climbs up, and then, and there, he gets a new hammer. a new promise. a new oath.
i understand now. my place was always here in the lab with you
