To save Yoshino, Shido crosses a five meter barrier that would likely have killed him despite his Healing Factor. He survives.
Efreetcurbstomping Kurumi, who had earlier taken down Mana, Tohka and Origami with ease. You don't usually see a Time Master get defeated this easily.
KyouheiKannazuki successfully defending the Fraxinus from the Arbatel's attacks using the ship's Realizers with pinpoint defences, and getting in a sneak attack with a Realizer while already controlling 7 Realizers' worth of generated mana, certainly counts. That's right, he was controlling 8 Realizers with pinpoint accuracy, where most people can only do 1. And he made the whole thing look easy! No wonder he's the vice-commander of the Fraxinus. If not for his masochistic tendencies, he could've easily become the commander instead of Kotori.
Shido protecting Miku from Dark Tohka when Miku's spiritual energy runs out and she can't defend herself. Also counts as Heartwarming since earlier on, he had promised to risk his life to protect her if she were ever in danger, and she didn't believe him, having lost trust in humanity, especially guys, long ago.