Also from Project: Superman, after Kal-El and Lois Lane meet as children in Project: Superman #2, and after General Sam Lane and Subject Zero are sent into the Phantom Zone, General Adam puts Kal in a tiny cell and basically tells him that he has to agree to be a living weapon or he will be kept there forever. As if that weren't heartwrenching enough, the final scene of the issue is Kal-El carving a little scribble of Lois into the cell wall with his heat vision, knowing very well he will never see her again.
Dick Grayson losing his mother, then his father, in the aftermath of an Amazon strike-force sent to get the Helmet Of Nabu.
Batman asking the Joker whether he should help the Flash rewrite their timeline and restore the true one. Thomas Wayne is asking his wife whether they should sacrifice their lives to save their son. In a touching and intimate moment, where Martha acts temporarily sane, she agrees. But Thomas has to admit to Martha that Bruce will become Batman, driving her to tears, while Thomas himself looks regretful.
Tears nothing. Upon learning that her son will become Batman just like his father (to her with everything that implies) she runs off crying & screaming while Thomas is trying to catch her. She throws herself into the Batcave to die in the fall because she can't live with that knowledge.
To restore the timeline, Barry must let his mother die again.
Parker talking to the subject in "Who's George?": an ordinary guy who lost his job and is desperate to get money to pay for his wife's retirement home. And to make matters worse she suffers from Alzheimer's. And then, despite Parker's every attempt to prevent it, the suspect succeeds in pulling Suicide by Cop, so that the insurance payout will take care of his wife.
Some of the episodes have tragic examples of Miscarriage of Justice, notables being "Never Kissed A Girl" and "Team Player".
Subverted in "Collateral Damage" , where the suspect is proven to be innocent at the end of the episode before actually being placed in jail.
Lewis'sdeath. When it becomes clear that any attempt to rescue him would most likely endanger the life of another officer, he waits until Spike has walked away try to get more equipment for an attempt everyone thinks is risky and steps off the landmine.
The reaction of the team made it a hundred times worse. The image of Parker cradling a crying Spike was just heartwrenching to see.
The reveal that Wordy has Parkinson's disease, and his subsequent decision to leave the team.
"Broken Peace", oh boy. Ed has to kill an 18 year old girl after she opens fire on the subject (who was her father) in an attempt to protect her mother. The resulting has a Villainous Breakdown from the father (whose daughter is now dead because of his violent actions to try to see her), a team wide Heroic BSOD and Raf leaving the team at the end of the episode. Ultimately, one of the more heartbreaking moments in the series.
Ed again confronting his PTSD with his psychiatrist in the episode "Fit for Duty" is just as heartwrenching. The events listed in the episode above are revisted.
Parker talking about his time when he was The Alcoholic, hitting rock bottom, and how he couldn't stop and it made him lose his wife and son. And after eight years, his son refused to see or speak with him, sending back unopened letters and not coming out of the house to see him.
Parker: "I took a leave from the job. Holed up at home, case of vodka and a promise: either I finish these bottles or they finish me."
Moments after rushing to the scene of the explosion at a Health and Wellness Center, Jules discovers the lifeless body of a boy outside the building. She somberly says "I'm sorry" and places a death tag
The discovery that Ed's son was severely injured during another explosion at Toronto city hall. Ed's desperate look on his face makes it all the more sad.
Donna's Heroic Sacrifice death at the end of the first part of the finale. She and other Team Three members are violently killed in yet another explosion when they discover the teacher with the explosions was used as a patsy.
What makes it worse was that the SRU members were too busy handling other dangerous situations to mourn her loss.
After Ed shoots the accomplice, he runs to cradle a wounded Parker tearfully pleading him not to die.
The final scene of the second finale episode where the SRU members have one final toast dedicated to Lou and Donna. May also count as a Crowning Momentof Heartwarming.
Lastly, the montage at the conclusion of the the finale highlighting key moments of the series.
"Haunting the Barn". A veteran SRU member (and Ed's mentor) cause a fake bomb threat, so he can kill himself in the briefing room over guilt, from an incident that happened 20 years prior.
"Behind the Blue Line". After Sam spends the majority of the episode trying to talk down, a former soldier suffering from PTSD over the death of his friends in Afghanistan, Sam is helpless to stop him from essentially instigating what is suicide by cop.