At that moment, the dynamite explodes. At the very least, the Legionary is killed by the explosion. The explosion should be enough to destroy the securitron, but it's hard to tell through the smoke.
Aurelius isn't on the barge, he's standing on top of the command building, firing wildly below him and tossing dynamite everywhere. He watches as the barge explodes and begins to sink, taking everyone onboard with it. He is shocked, not at their deaths, but that the Courier might be capable of such cruelty. He smirks. He'd have made a fine agent of the Legion had he not gotten delusions of Grandeur. He is so tickled by the notion, in fact, that he begins to laugh, crazed by battle, the sound rising above the tumult. "So this is the great and mighty Courier Six!" he roars between peals. "Killer of defenseless women and children!" He doubles over in laughter. "So this is what your freedom looks like! The freedom to die! HAHAHAHAHAHAHAHAHAHAHAAAAAA!!!"