Winter doesn't move with the crowd at first; he spends a second or two gazing down at Aslan's body with a look of quiet sadness, and then just as the last of the horde streams past him and none are left to see him do it, he undoes the muzzle over the lion's mouth and drops it on the ground.

As he turns to follow the rest of Jadis's creatures, his eyes pass over James and Bella's hiding place with barely a pause. He doesn't stare or cry out or indicate in any other way that he saw them; he just starts after the trailing end of his Queen's army, slower than the rest of them but still quite fast enough to be gone in the space of a breath.