Dumb It was a bit hazardous to warp into anti-matter radiation, but DC Antimatter was specially-made to mitigate destructive capacity in all but the core ships, which aren't as efficient at mitigating such a dramatic combustion (Destroying Coreships is a big deal, so much so that I avoid situations where they would get one-shot. Subcores are okay, though.) So I suppose your blockade runner got lucky.
What troubles me, however, is that now you took away the reward for the Blood Cult for your own faction.