Well 'Smashed' is certainly not a precise term to apply to cable / wire. . and in this case where reading between the lines the ELT case was closed with the ?battery? leads out of place you would expect some more precision (crushed, crushed together, flattened, split, nicked, trapped etc.)
(And like the other poster I'd think unless the battery fusing was incorrect, omitted or failed this short circuit should simply have blown the battery protective fuse (s) before the battery could overheat.)
You end up thinking the presumed short set fire to some other component in the ELT and that fire then spread to set the battery off . . except very few professional grade electronic components burn for long or that well in a sealed container. . .