Wait, Argus don't! Think about what Aornis would do! Killing yourself won't bring you anything!!!

My goodness given his life, and what he's about to do its a wonder he didn't have a heart attack

Oh god, it's The Knife™

YIKE

Oh dear. :/ In his head, he wants to be with the one person who cared about him. :/ This is not good and is so taboo. Not good at all.

"I was so concerned with myself… So burdened by the weight of my own heart… I never considered that a man with no heart is a beast."
(Act 2, Chapter 1: 32-33)

There goes the hemlock potion...but then Argus sees Aornis's collar and the knife he used to cut her throat, which he was told was a quick and merciful way for her to die. So he's probably getting it into his head now that using that knife on himself would have the same result, even though that death wouldn't be nearly as clean for him, because it's much harder to manage than drinking poison would be.