Aldnoah.Zero was not a great show. It began as a skeleton of a decent mech series cobbled together by some obscure guy you might heard of that goes by the name of Gen Urobutchi, before completely handing it off to script writer Katsuhiko Takayama. This ended about as well as the time he handed of Gargantia on the Verduous Planet, which means the show only manged to get worse as a result. The one constant throughout the series was the frequent dullness of Inaho Kaizuka, the aforementioned “world’s greatest military mind” (because he’s the only one who can formulate a strategy beyond “stand and shoot at a target who isn’t at all affected by bullets” or “remain in place because we need death fodder to make the Martians look more threatening”) and the show’s incessant need to drag Slaine Troyard’s face through the mud. It isn’t until these two characters are brought together at the end that the show’s crowning moment of dumb comes into light.
Even before getting into the cliffhanger, some of the moments that lead up to it were real headscratchers. Such as Inaho’s refusal to trust Slaine at the very least until the end of the mission and try questioning then back when they first met, or Slaine’s refusal to answer questions or even try to come to any sort of understanding (probably written this way to force tension between the two). There’s also the matter of Slaine choosing to assist Saazbaum when he made it clear that he was after the Princess’ life. He even acts completely surprised when he actually guns the Princess down when it was his own goddamn fault that it happened. Things like this serve as a horrible justification for their “rivalry” which wouldn’t of any reason to exist. These aren’t characters, these are empty purveyors of cheap drama.