Doctor Terrence Parker

Terrence Parker (age: 40s) is a doctor at Mercy Hospital who is tasked with treating the neurologically damaged teenage victims of the Maudling's tainted ecstasy pills.

Personality and Addiction
Terrence is shown to be personable and well-liked, seeking to befriend each new person he meets as quickly as possible. Despite his outgoing personality, however, Terrence is shown to suffer from depression and an addiction to narcotics that he steals from the hospital. In a conversation with DEA Agent Rashad Jones, he reveals that his wife died in a car accident several years ago. The implication is that his depression and addiction stem from grief over his wife's death; however, in season 3 it is revealed that he cause the fatal car accident by driving while intoxicated and falling asleep at the wheel. In season 4, Terrence attends a Narcotics Anonymous meeting, but fails to follow through with the treatment program after an attendee's comment that "You can't undo the past" upsets him.

Friendship with Rashad Jones
After reporting the epidemic of tainted ecstasy pills to the DEA, Rashad becomes his main point of contact. Over the course of season 2, their professional relationship turns into a friendship. They will go on to regularly drink together at Applebee's. When Nurse Hope Conners is caught stealing narcotics from the hospital and falsifying records, Rashad interrogates her and she confesses that she was stealing the drugs on Terrence's behalf. Rashad confronts Terrence who breaks down and promises to seek help. Rashad allows the case to fall through, betraying his internal moral compass to protect his friend.

Collaboration with the Maudlings
In season 4, it is revealed that Terrence has been faking patients' deaths and secretly transporting them to the Maudling compound. The Maudlings had promised to bring back his dead wife using their advanced technology in exchange for human test subjects.

Coma
Upon seeing Rashad in captivity in the Maudling compound, Terrence is overcome with guilt and begins to drastically increase his drug and alcohol consumption. After breaking every mirror in his house, he retrieves a pistol from a shoebox in his closet. After contemplating suicide, he ultimately decides to go back to the Maudling compound, with the apparent goal of rescuing Rashad. During the drive to the compound, however, he falls asleep at the wheel and crashes, mirroring the accident that killed his wife. The accident leaves him in a coma that he does not awaken from before the end/erasure of the series.