The torpedoes are large and unstable due to their being early prototypes of antimatter missiles. The instability part comes from the problem of power - if the carrying ship loses power, the magnetic containment "bottles" fail and everything goes boom.
Why in the name of the great sky engineer don't they have back up power just for those magnetic bottles? Batteries in the torpedoes at a minimum?
They don't even have to last that long, just long enough for an emergency protocol to flush the magazines into vacuum (via explosive bolts or something!)
Does no one in the Imperium have a lick of safety sense?
