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Tear Jerker: Medium
The finale of the two-part episode Wicked Games. Cynthia Keener avenges her daughter Suzy's death by shooting Suzy's killer and immediately turning herself in for it. Allison sits and holds Cynthia's hand while waiting for the police to arrive.
When Joe and some colleagues are held hostage by a disgruntled former employee, his boss realises that the gunman only has time to shoot one person. The reason he only has time is because his boss dives on the gun and blocks the guy from taking aim at the other two (Joe, a father of three, and a pregnant woman). Sadder still because the boss mentioned in passing that he and his wife were going to the opera that night. Even sadder when you realise that the gunman was only doing it because he had a terminal illness and wanted to support his family.