That'd work better, if not for the snow. He's still physically there, so where snow hits him, it first disappears from sight, then melts against his skin and drips down as water. As a result, he's leaving a transparent silhouette where ever he happens to be. Not noticeable from a hundred meters away... but pretty obvious from, say, ten.

The man in the black jacket notices Koutarou's sudden disappearance and is visibly alarmed by it. He steps away from the wrecked car

"So wait a minute... did I get this right? You screwed them over, and now you're trying to dodge explaining or taking any responsibility for yourself? That's ****ed up."

The girl looks like she doesn't know whether she should cry or laugh. "No, Ishinomori Koutarou. I know you all too well. And like usual, you never fail to dig yourself deeper. But it looks my time here is up. So if you'll excuse me, I'll finish the mission I came here for."

She stands up and leaps towards the wrecked car. Behind her, Koutarou can already see reflective vests of the approaching rescue personnel peek through the snowfall.