- Martínez: "Listen, man. I need a broad. I need Mary. Mary, Mary, quite contrary! Ha ha! Come on, man! I need a favor."
- Vic: "I need you to collect your pot, dude."
- Martínez: "Sure. I'll go get that from your quarters and you go get Mary for me, OK? She's over in Viceport."
- —Jerry Martinez makes a deal with Victor Vance
Conduct Unbecoming is the final mission in Grand Theft Auto: Vice City Stories given to protagonist Victor Vance by army sergeant Jerry Martinez from his office in the Fort Baxter military base in Vice City.
Victor Vance goes to see Sergeant Jerry Martinez, who is watching a Candy Suxxx film. Martinez tells Victor to find and bring back a prostitute called Mary. Victor questions Martinez about the drugs he is hiding and Martinez says he will take the drugs whilst he is off base, and tells Victor to see Phil Cassidy for a gift.
Victor drives to Phil who has a red Stinger for Victor from Martinez. Victor drives around Viceport looking for Mary, but instead finds another prostitute called Mona. Mona informs Victor that Mary is at a party on Starfish Island. Victor drives Mona to the party and then finds Mary, saying that they are leaving. Two party goers, who have paid for Mary's services, decide to put up a struggle, but are killed by Victor.
Victor drives back to Fort Baxter military base with Mary and is met by Sergeant Peppah. Sergeant Peppah questions him about the drugs and then about Mary, before kicking Victor out of the army. Victor, in civilian clothes, gets paged by Phil Cassidy, saying he has both work and a place to stay. Victor goes to the home, 101 Bayshore Avenue, and the mission is completed. After this Victor refuses to do any more work for Martinez.
In order to complete the mission the player must:
- Meet Phil at his old place
- Look for Mary around Viceport
- Pull up to that girl and ask about Mary
- Take the girl to the party
- Protect Mary from these violent assholes
- Take Mary back to Fort Baxter
- Head back to Phil's old place
However, completing the mission will also result in Vic losing all weaponry collected up to this point, the Stinger he receives during the mission (he does not gain access to a garage until after the mission ends), and he permanently loses access to the Barracks Safehouse and its safe point, though the pistol spawn point inside briefly becomes accessible again during the later mission Over the Top.
- The soldiers that confront Vic do not use the soldier model used at Fort Baxter Air Base, but the model that is seen during a six-star wanted level.