Honestly didn't think the Torpedo Launcher was affected by Explodifier. Multiply that by the Torpedo's already massive attack power of 200 (!) combined with a bunch of other damage boosts... I have no trouble believing that combo annihilated Terminus like that.
I've been testing different values for that weapon lately but even at half the power, it still packs a lot of punch. I definitely underestimated its firepower originally, that's for sure.