"Suicide is painless" is a play on words also. It refers back to the dentist on the original MASH movie (not the tv show).
From wiki:
Father Mulcahy, the camp's chaplain, tells Hawkeye that Walt "Painless" Waldowski, the unit's dentist, has consulted him about a problem. Mulcahy feels unable to divulge any details because Walt confided in him during confession. Waldowski tells Hawkeye that he suffered a "lack of performance" with a visiting nurse and now believes he has latent homosexual tendencies. He wants to commit suicide, and asks advice on a reliable method. Hawkeye, Trapper and Duke suggest that he use the "black capsule", a fictitious fast-acting poison. At a farewell banquet that satirizes The Last Supper, Walt takes the capsule (actually a sleeping pill) and falls asleep in a coffin. Hawkeye persuades Lt. Maria Schneider to spend the night with Walt and cure him of his "problem."
_________________
"Them that don't know him don't like him,
and them that do sometimes don't know how to take him;
He ain't wrong, he's just different,
and his pride won't let him
do things to make you think he's right."
-Ed Bruce