Gut-wrenchingly painful story. Hell hath no fury like a Rodney McKay whose friends have been slaughtered, effectively right before his eyes. I don’t see Rodney having descended into madness - I think he’s perfectly sane. But once he realizes his dearest friends are all dead in spite of all his efforts, everything inessential is burned away, leaving only his purpose. He will burn the galaxy, if not the universe, on the very long way to his grave. Or perhaps, he will only burn the tyrants, the despots, and the greedy, leaving the ordinary and innocent free to rebuild their lives.