Possible Clues:

• Confine - person on work experience
• Will one find 'er shut in in the bird?
• During winter no-one is put in prison
• One might get the North underground so as to shut it up
• Lewinsky was one
• What doctor is to keep under lock and key
• Confine - physician in US hospital
• Exercising some self-restraint, Ernest shut up
• Just shut up, one after the other, by the sound of it
• Hospital doctor (US)