The constriction came from an arm around his neck, but he couldn't see to whom it belonged, and there was no place to move aside in the corner of the egg.
They left him alone inside the egg. 
mnli hypothesis: They left him alone inside the egg.  premise: The constriction came from an arm around his neck, but he couldn't see to whom it belonged, and there was no place to move aside in the corner of the egg.