I can think of a couple options. Push original-Trowa's death way earlier, back to shortly after the hatching, or have the scientists assure o-Tro that all that nonsense about telepathic bonds is romanticized literary invention and of course he's not supposed to hear her ahahaha *milk the Bartons for money while Heavyarms' "young stablehand" does all the plebian work o-Tro is naturally not required to do*. And then o-Tro goes crunch right before the big drop.