Green heads down to the M.E. Working a foxy Helen Mirren hairdo, M.E. Rogers, I think it is (...?), says she got his message, and when he's like, "In the what now?", it turns out Green didn't call her -- Lupo did, using Green's name because nobody at the M.E. knows him. Awkward! In any case, Thomas's cancer had returned, as Lupo suspected when he found the painkillers; Thomas had about three months to live. And the official cause of death is an overdose, all right -- of potassium chloride, the same chemical used in lethal injections.
At the precinct, Green and Van Buren talk about how Thomas put his affairs in order, which makes it seem like a suicide. Lupo doesn't want it classified that way, because the case will get buried; Green's like, we've got actual murders to solve here, and maybe Thomas "had good reasons to take a shortcut to the exit -- maybe if you'd called him back and talked to him, you'd know why." Damn, Green. Four minutes, unnecessary roughness. After an uncomfortable moment, Lupo asks for permission to work the case, which Van Buren obviously denies. Then her phone rings, and as Lupo stomps out, Van Buren hangs up and tells Green to saddle up: "Someone else just took a shortcut to the exit."
The next victim, Driscoll, is slumped in his wheelchair; he died the same way Thomas did.
Rogers briefs Van Buren on the tox cocktail found in both victims -- a heavy-duty sedative, a paralytic, and the potassium chloride. It sounds familiar to Van Buren, and Green supplies that it's the same cocktail used by Dr. David Lingard, a.k.a. "Dr. Death," a.k.a. "please don't sue us, Jack Kevorkian." Lingard is an assisted-suicide proponent who admitted on TV to killing his patients and was convicted of murder; he just got out of jail a month ago. Rogers leaves, and Van Buren and Green look at Lupo across the office, where he's been pacing for hours. Van Buren then talks up Lupo's overseas service, and says Lupo isn't related to the second victim: "It wouldn't be a policy violation for him to work that case." It would be a contrivance violation, but it's not like we don't know Sisto's a regular, so let's just go with it. Green isn't thrilled...
...but the next scene finds Green and Lupo at the Lingard residence, where Lingard is naturally denying everything because it's only 18 minutes in. Lingard is played by Brad Dourif, which is a black bit of casting humor given Dourif's breakout role, and he's speechifying about how he knows the terms of his parole, and he can't so much as give advice about how to commit suicide, even though people ask him all the time. Then he gets up on a right-to-die soapbox that I feel like we've seen on at least 14 past L&O episodes. Lupo presses him, but he won't admit to anything.