In The Americans, why does William Crandall break the glass vial holding the Lassa virus (which is lethal and gruesome) and stab his hand with it, fatally infecting himself? He was terrified of the virus, and reluctant to "play a part" in possibly spreading it. Also, while he was very unhappy with his life, there's no sign he was suicidal. It's been suggested he did it to distract the FBI from capturing Philip and Elizabeth, but that doesn't seem like a strong enough motivation to me.
He destroys the virus that way:
It’s life-and-death drama, but it resonates to the show’s emotional core, too. William’s acting selflessly when he contracts lassa so no one else has to (there’s something messianic about those wounds in his palms, right?) but that means Elizabeth’s work with Young-hee and Don was definitively in vain.