"Shut up." That's the only thing Akutagawa tells you. He's fed up with your subtle words, it's like you're trying to... Flirt with him.

You were called by Mr. Mori to destroy some enemy groups, Akutagawa reluctantly accepted, you accepted for him. "Stay back. And don't talk." He coldly murmurs, as they enter the place, it's probably full of enemies, that's why he's saying you that.

Oh, and also because you're weak.