Warning: Major spoilers ahead for episode 10 of MobLandThe which led to Freddie's death). After hinting at the rat's identity in episode 9, the rat was confirmed to be O'Hara Delaney, who had been feeding Richie intel about the Harrigans for nearly a year.

However, when Harry called O'Hara to his office to have her confirm her betrayal in person, he did not kill her as most would have theorized. Instead, he made her an essential cog in his plan to end the Stevenson crime organization in a span of just minutes. By sparing O'Hara and giving her an opportunity to redeem herself by helping Harry take out the Stevensons, it seemed as though he might have forgiven her, especially given his own hesitations regarding the stability of the elder Harrigans. However, she still didn't survive Harry and Kevin's final showdown with Richie Stevenson.

Harry Had No Choice But To Kill O'Hara, Despite Her Helping Bring Down Richie

As A Rat, She Could Never Be Trusted Again

When it finally dawned on Richie that he was defeated and undefended after Harry and Kevin gunned down his guards, the crime boss grabbed O'Hara just after she taunted him one final time. Richie used her as a human shield against Harry and Kevin as they stormed into his office, but it did him little good. Harry immediately shot O'Hara through the chest, causing her to drop and leaving Richie open for the men to pepper him with bullets. O'Hara survived that first shot, but once Richie was handled, Harry coldly shot her in the head, killing her instantly.

O'Hara Delaney was portrayed by Lisa Dwan, who recently starred in MobLand creator Ronan Bennett's other prestige crime drama, Top Boy, as Lizzie Kilfauns.

Despite proving her loyalty by helping take down the Stevensons, Harry had no choice but to kill O'Hara given her status as a rat. Harry cleverly used Richie's trust in her to his advantage, but once his plan had run its course, there was no way to ever trust O'Hara again. On top of that, it's unacceptable to have someone betray a crime family (especially one as powerful and exalted as the Harrigans seem to be) and continue to live. Even if Harry wanted her alive, there is no chance that the bloodthirsty Conrad would ever allow it.

O'Hara's Death Continues A Big Theme For Harry

Several Of His Murders Are Uncomfortable To Consider

Harry is responsible for some of the most brutal murders in the entirety of season 1 of MobLand, and the biggest ones are even tougher to stomach when they're examined. Three of his most significant murders, the last of which was O'Hara, came directly after his victim did something to either protect or assist Harry or the Harrigans. Without O'Hara, there's no knowing what the death toll for the Harrigans' side of the conflict could have been. Before her, Freddie Shaw was trying to exit the criminal underworld entirely, and gave Harry the information he needed before he was killed.

Harry's murders are difficult to stomach given the cooperation of his victims, but they're all ultimately necessary to protect himself and the Harrigans.

Earlier in the season, the bar owner Valjon literally lied about killing Tommy Stevenson directly to Richie, and even held his tongue despite Richie's torture. His reward was Harry viciously stabbing him with a broken piece of wood, which highlights the paradoxical nature of Harry as a character. He is the closest thing to the main protagonist/hero that MobLand has, yet he suffers under the burden of working for the Harrigans and being good at his job. Harry's murders are difficult to stomach given the cooperation of his victims, but they're all ultimately necessary to protect himself and the Harrigans.