Private Carter, a wounded soldier who arrives at the 4077th, appears in the Season 2 episode of M*A*S*H titled "Deal Me Out". The part of Private Carter is played on the series by John Ritter, who, at the time, was appearing on the CBS-TV series The Waltons as Rev. Matthew Fordwick, would later achieve TV stardom as Jack Tripper on the long-running ABC-TV series Three's Company.
About Pvt. Carter
Private Carter, a battle distressed and shellshocked soldier who, in refusing to go back to the front, holds up Major Burns, who was in the shower, hostage at gunpoint, threatening to shoot him if the 4077th didn't provide with a helicopter taking him from the camp to a plane headed stateside. Frank almost gets it with his gung-ho Army talk, until he realizes it's best to remain quiet, while Henry and Major Sidney Freeman, who once treated him before, try to talk him down from his demands. Somehow, however, Trapper manages to take Carter down, rescuing a panicked Frank in the process!
The theme of an unstable patient taking a MASH Officer hostage was repeated in What's Up, Doc with Winchester being the hostage.