Usually when people get killed in crime dramas or murder mysteries, nobody shows any remorse or emotion. If anyone does, it is because they are the culprit trying to distract attention. Sometimes you see a bit character who goes hysterical for a short scene, but these characters are ridiculed as unmanly, homosexual, scatterbrained, irrational or even comic relief ("I told him, Julie, don't go.")
The most emotion you might see is one cop say, "It was too bad someone so pretty/young/talented/sexy bit the big one. She didn't deserve this. Let's nail the bastards who did this".
In this episode, one of the regulars, Greggs, is shot in the line of duty by drug dealers, and is in hospital. It is nip and tuck whether she will survive, or recover sufficiently to continue her role.
In this episode, some of the other regulars react much more like real humans would, with anger, despair or sadness. They are so distraught that they cannot function. They do what they can to help each other through it. They also show the suffering of her lover, in a quite realistic way.
It was an unusually moving drama. The actors were quite convincing and tugged at your heartstrings. It was almost TOO intense.