caj,
You ask “Who is responsible for the locksmith fees?” I would have thought it is the OC. Probably the lock and door are common property anyway but Section65 of the Strata Management Act provides at subsection (6) that:
An owners corporation is liable for any damage to a lot or any of its contents caused by or arising out of the carrying out of any work, or the exercise of a power of entry, referred to in this section unless the damage arose because the owners corporation was obstructed or hindered.