dear friend across the river
This is all just pointing out the obvious, but I love how well Arcane seeds its final tragedy even from its first few moments. There are multiple excellent relationship arcs in play leading up to the end, of course, but even from the very beginning we can see the effect that the violence of the world has on Powder and everyone else growing up in the Undercity.
Vi no doubt told Powder to keep her hand over her eyes and not look on the bridge, but it’s clear even at this age - even before their personal loss is revealed - that she’s fully aware of the conflicts and the cost of the war being waged and the unflinching brutality of the Enforcers, and a part of her is already deeply wounded by it - right from the very start are the same jagged mental sketches we see later on, superimposed on the world whenever Jinx is having a particularly bad time.
It isn’t just one chance flip of a coin that leads to disaster, but the escalation of tensions over time. Vi and Silco’s choices and actions played a role toward the conclusion, but the seeds were sown much earlier than that.
It isn’t even a direct line of fault from the top - Jayce and Mel weren’t anywhere near positions of power when the last bridge riot was so violently halted, and Mel has already proven that she will choose mercy over caution when push comes to shove, even to her own detriment.
The closest there is to someone who had power at that time was Heimerdinger, and he’s as gentle, benevolent and concerned with the greater good as anyone could be. A young Powder would probably get along with him just as well as Ekko did later on. But he wasn’t there, and by the time he realized that caring about the Undercity might be a good idea, it was a decade too late.
We even are shown that the Enforcers aren’t the faceless, unstoppable monsters that Powder knows them as. Some are greedy and underhanded and brutal, out entirely for themselves, while others are simply working for a system they’re not in charge of, trying to keep a peace they are well aware is untenable.
The system was broken, and hurt itself as much as anything or anyone in the pursuit of power and control, and Jinx is the ultimate expression of all of that.