Surrounding walk radical (Kangxi #162) — three strokes, a stylised foot-and-step (the simplified form of
辵). Wraps from below-left around the right and bottom. Carries the meaning:
遭 'to meet with, encounter, run into' is fundamentally a movement-and-meeting verb. Same radical anchors
进 (advance),
退 (retreat),
过 (pass),
还 (return),
逃 (flee),
遇 (meet) — the entire travel-and-encounter family.