This is initially going to sound dismissive, but bear with me:
Takumu is very much a character with a Worf-type role; he's gone down first in every major confrontation thus far. He almost serves just to pad out the time until Haruyuki gets to be the hero.
This is all sadly predictable, and one of the reasons I dislike having a designated hero among the protagonists. More and more, I am growing disgusted with the idea that only the designated hero is allowed to save the day, and that his friends are all merely sidekicks who exist to enable his victories (or just pad the time).
Thankfully, Takumu usually acquits himself admirably in combat, such that I do not fault him for his losses.
I said "usually", though. The sole exception to his admirable performance would be his loss against Haru in their first battle, since Takumu's defeat stemmed entirely from a loss of his usual tactical judgment.
At the point that Haru discovered his ability to fly, Takumu had far more HP left. If he had simply retreated back into the hospital building, he would have robbed Haru of the only advantage he had.
Their initial engagement had made it abundantly clear that Silver Crow was no match for Cyan Pile in the tight hallways, especially with the Pile Driver's ability to reach down the corridors. The low ceiling and narrow walls would eliminate Silver Crow's flying evasion, and the intersections (or doorways) would let Cyan Pile hide from any flying charges while striking at Crow as he passed.
And if Haru didn't follow him back into that death trap? With his lower health, Silver Crow would have lost to time-out.
But Takumu had lost his cool, and didn't think about the fight rationally. He became caught up in proving his superiority in a straight-forward confrontation without the use of tactics. Otherwise he would never have done something so risky as try to hit a FLYING target with a straight-thrust attack like Cyan Lightning Spike.
At the very least, Takumu could have tried another Splash Stinger when Haru inevitably dove at him. Haru couldn't attack from any direction but head-on, and Splash Stinger would have a wide enough strike zone and deal enough damage to reliably end the fight in Cyan Pile's favor. Also, the Splash Stinger doesn't require rooting himself to the floor, so Pile could have DODGED Crow's dive.
Of course, even if Takumu had kept his head and played smart, he still would have failed his real objective so long as the fight lasted long enough (after the "wing moment") for Kuroyukihime to wake up.