Akechi isn't entirely sure what compels him to act. Perhaps it's instinct, some side effect of his recently accrued changes, but the moment Donnie reacts with discomfort at the metal down below, he thrusts a palm out, and...

A cool, icy blast fires from his hand, leaving him in wide-eyed stupor.

"...Interesting."

It might help, but it's too new of an ability for him to fully weaponize it here. Instead, he'll take this opportunity to move forward.