Subject is always a crowd (
球迷,
游客,
难民,
观众), never a single person. Near-synonym
涌入 (yǒngrù) is interchangeable in most contexts and slightly more common;
拥入 emphasizes the physical pressing/throng (
拥 = to crowd/embrace). Both contrast with
涌出 /
拥出 (to surge out).
