Root assumes she's dead at first. There's quite a few reasons to draw this conclusion: her clothes are bloody but the wounds under them are closed up, scarring nicely already; the sky is cascading colors across the night, not just an aurora but a whole spectacle of the universe; and she's stuck in a frozen hellscape with the wind whistling past her. She finds Bear just as her fingertips start to fully freeze and the two things together convince her she is not, in fact, dead, or at least not in any way that matters.