By all means keep your halon and use it first in case of a fire.  I think
what I would try with one of these is to hose the fire real god then quickly
slam the lid to contain as much halon as possible.  Be sure to ventilate the
compartment very well before you go poking your head in to look at the
damage.  And I'd have a CO2 for back-up just in case.

Chuck