You'll note a couple of things.  There is NO reference to a Police Officer in the above.  Its ANY PERSON.
Secondly is that the force is not disproportionate to the objective.

Thirdly - to prevent the commission of an indictable offense

Can't be a low level sort of thing, don't want members thinking they can go around arresting people for dropping litter!!

Not sure if that applies to any power granted to an armed force as it's just the Victorian Crimes Act, and armed forces are under Federal jurisdiction.

No doubt the police are going to need some better equipped back up pretty soon if this keeps going, it's hard to understand how this has spread to different areas, seemingly unrelated.