Possible Clues:

• N.I., one by one
• Elected to pass one after the other
• How board game players play
• One of the trainee doctors you may see, it's rumoured, sequentially
• In proper order or sequence
• One after another go to bed, but in the wrong order
• Shut up, listening as a succession of things happen
• Report of trainee being given orderly treatment
• Succesively
• Say detain a soldier by agreed order