SPOILER WARNING: This article contains major spoilers for "Living Proof," the latest episode of Arrow.
In "Living Proof," the penultimate episode of Season 7, Arrow saw the return of Colin Donnell's Tommy Merlyn, who died during the attack on the Glades in Season 1. He appeared to Oliver when he was trapped beneath the rubble of a demolished building, as nothing more than a hallucination.
After his sister Emiko detonated bombs that brought the building down around him, Oliver woke up pinned between two concrete columns. He extended a hand to reach for an arrow, only for it to be kicked to him by Tommy. When Oliver looked up and saw him, he knew immediately that Tommy wasn't real.
"Oh, I must have a really bad concussion," Oliver groaned, to which Tommy replied, "Yeah, man. A building just collapsed on you."
As Oliver attempted to think his way out of the situation, Tommy discussed the issues at hand, including Oliver's intentions for Emiko. Oliver was determined to stop Emiko by any means necessary, even if that meant killing her. Tommy, on the other hand, insisted this would only perpetuate the cycle of violence and hatred that Robert Queen created.
Frustrated, Oliver eventually snapped, "You're not here. You are a figment of my imagination that has been sent over here to test my resolve."
Nevertheless, Tommy's words got under Oliver's skin. So, when Oliver believed he freed himself, he saw himself kill Emiko -- only to turn and see his team dead on the floor around him. This snapped him back to reality, where he realized he had been trapped between those pillars all along. However, between Tommy's words and this vision, he had plenty to think about.
Eventually, Oliver and the rest of Team Arrow made it back to Star City Police Department, where they discovered a Ninth Circle massacre in progress. Oliver spotted Emiko and gave chase, only to confront her on the rooftop. Instead of killing her, as he told Tommy he would do, he tried to reason with her.
"Haven't you seen enough death? Your mother. Our father. I want you to be better than him," Oliver begged. "I want you to help me end our family's cycle of violence." She scoffed at the idea they were family, then demanded he kill her. After a long pause, he simply replied, "No." With that, she took off, holding a weapon that could spell the end of Star City.
Airing Mondays at 9 p.m. ET/PT on The CW, Arrow stars Stephen Amell as Oliver Queen, David Ramsey as John Diggle, Emily Bett Rickards as Felicity Smoak, Rick Gonzalez as Wild Dog, Juliana Harkavy as Black Canary, Colton Haynes as Arsenal, Kirk Acevedo as Diaz and Katie Cassidy as Black Siren.