WARNING: The following contains spoilers for The Good Doctor Season 4, Episode 15, "Waiting," which aired Monday on ABC.
After an emotional episode that saw Shaun Murphy accept that he had to defer to his girlfriend Lea when making decisions about the birth of their daughter, The Good Doctor is back and ready to tackle some heavy subject matter. "Waiting" opens from the perspective of two different children arriving at a political protest; the first child, Ethan, was dragged there by his mother and just wants to go play video games at a friend's house, while the other, Mason, is so excited to attend, he made his mom a special bracelet.
The episode then cuts to Shaun and Lea back inside San Jose St. Bonaventure Hospital, just as they hear about two gunshot victims being brought in from the protest. With two teams ready to handle the situation, Mason is the first to arrive with three gunshot wounds in his chest. Claire, Asher and Dr. Andrews get him stable enough to take him to the operating room, but the second crew may not have as much luck. Ethan arrives with a gunshot wound to his head, and as Shaun, Park and Dr. Lim take him away, things look grim.
Both of the boys' mothers sit in the same waiting room as Lea, who is waiting for the results of a test, and she offers to help them fill out hospital forms as their sons are in surgery. However, as the two women begin to bond, Ethan's mother, Taryn, realizes that Mason's mother, Karina, was on the opposite side of the protest, and she asks her to stop speaking with her. Meanwhile, in the O.R., Claire, Asher and Dr. Andrews begin debating their opposing viewpoints on politics when a complication happens during Mason's surgery.
Back in the waiting room, Claire and Asher inform Karina that he may have lost brain function, but they need to wake up to fully assess the situation. Without any hesitation, she agrees to go through with it because she lost her husband in a car accident and wants the opportunity to say goodbye. Mason wakes up and demonstrates good brain function, but things aren't going as well for Ethan. The surgical team had to remove a portion of his skull to help the procedure along, which worries his mother, and things get even worse when Shaun discovers a bullet fragment lodged in his skull.
As Taryn begins to open up to Lea about her relationship with her son, Shaun and Park arrive in the waiting room to discuss the fragment. They believe it should stay put because it's unlikely to cause further damage, and after some convincing from Lea, Taryn agrees. Karina returns with the good news about her son, but things quickly take a turn after Taryn tries talking about her divorce. After some verbal jabs, Taryn loses her temper and blames Karina's side for the shooting at the protest.
Before things get any worse, Shaun and Claire both arrive in the waiting room with news on the boys. Claire informs Karina that the team didn't find any signs of brain damage, which was the best-case scenario. Shaun, unfortunately, tells Taryn that her son is going to intensive care because the part of the skull that was removed has to stay off until his brain swelling goes down.
But just as Taryn arrives in Ethan's room, she begins to notice that his eyes were moving and he was grabbing her hand. However, while she believes this is a sign that he's aware of his surroundings, Shaun quickly realizes it's a seizure caused by the fragment moving to the other side of his brain. Shaun, Park and Jordan take Ethan back to run more tests, and after finding the original fragment in its original location, they discover a second fragment that wasn't in the boy's original scans.
Shaun goes to Dr. Glassman for help, but he begins to realize that he might not be able to save Ethan, which makes him emotional. Park is also having a hard time coming to grips with the fact that he might lose a boy who reminds him of his son, Kellen, and begins to question if she should return to the surgery. But after a motivational talk from Morgan, his on-again, off-again love interest, he decides to go through with it.
Meanwhile, as Claire and Asher prepare to take Mason to his room, they find a blood clot in his leg, which they need to deal with immediately, or he's in danger of losing the leg. As that procedure goes on, Shaun and Park go to tell Taryn that there isn't more much they can do but wait and hope for the best. This upsets her greatly, so much so she shoves Lea, an act that causes Shaun to run to her side. Taryn then realizes that Shaun and Lea are together, and she was receiving advice from someone close to a member of the surgical staff, which leads her to storm off.
As Mason's condition begins to worsen, Claire and Asher tell Karina they don't believe he will last much longer without more blood. But just as things look hopeless, Taryn reveals she's a match for Mason and offers to donate the necessary blood. Park and Shaun then go back to the drawing board for Ethan, and Park realizes there's a way to remove the fragment without damaging the brain.
Both procedures end up a success, and after the two mothers embrace, they go see their sons in their respective rooms. Park then decides to head to the locker room, where he finds Morgan. He tells her that she's the one who deserves the credit for saving the boy, and while he thinks she's good for him, he wants to break things off and give another coworker a chance. And just as that heartbreak settles in, The Good Doctor delivers another blow when Lea collapses outside the hospital as the episode closes.