I'll just read the offence provision for you:
Every person who
(a) malingers or feigns or produces disease or infirmity,
(b) aggravates, or delays the cure of, disease or infirmity by misconduct or wilful disobedience of orders, or
(c) wilfully maims or injures himself or any other person who is a member of any of Her Majesty’s Forces
And then it goes on to talk about forces cooperating.
That's the way the offence is described in the act.