Clearly the fact that Akutagawa is no better than Atsushi in guarding his package is indeed irrelevant, because even Atsushi doesn't think to bring it up. Of course, that might also have something to do with the fact that he's sorta-kinda-almost-maybe fighting for his life here. (Would Akutagawa kill him, in spite of their agreement? Well, Atsushi doesn't consider him above it! It seems like a perfect example of killing two birds with one stone, from Akutagawa's perspective.)

Freed at last, Atsushi clambers to his feet and starts running again, though it doesn't last very long. It's barely a second before Rashoumon's jaws grab him, digging into his right shoulder and his lower back. He screams, but there's not much he can do: he tries, like the single-minded idiot this confrontation has made him, to just keep running, but that accomplishes little but tearing his own flesh... and his clothes.

With the back end of his suspenders being a primary casualty, his pants slide down somewhat behind, exposing his underwear and a strip of skin underneath, blood dripping down from his back over both. He freezes on the spot, shivering... but somehow it's not from the cold, the way it should be. Why does he suddenly feel so -...

It's probably only a moment that he can't bring himself to move with the throb of something running through him; outright forgets to move, even. But no doubt that is more than enough for Akutagawa to strike again.