[Oh, turns out he won't be alone the whole time after all. Nagito smiles, calm as he usually is.]

Not yet. I lost track of the footprints a little while ago. [It didn't occur to him to suggest to anyone they look for footprints. It seemed obvious to him, so everyone else must have known as well.] But assuming he's traveling more or less in one direction, it's just a matter of keeping track of the colors of the sand.