while undergoing treatment and rehabilitation in an approved centre escapes from the legal custody thereof;
(b)
while he is outside an approved centre escapes from the legal custody or control of an officer-in-charge of an approved centre; or
(c)
while he is otherwise in the legal custody of any other person escapes from the legal custody thereof,
shall be guilty of an offence.
(2) Any person who —
(a)
knowingly assists, directly or indirectly, any inmate of an approved centre to escape therefrom;
(b)
induces any such inmate so to escape; or
(c)
knowing that any inmate has escaped from an approved centre, harbours or conceals, or assists in harbouring or concealing that inmate or causes or induces him not to return to such approved centre,