Does she see him, or no? Her behavior is difficult to parse, but his suspicions remain. He does not know whether she will notice if she runs into him, as he has not yet made physical contact with any of the people who seem unable to see him, but as a precautionary measure he takes a measured step back out of her path as he turns to continue watching her as she goes by. He's waiting for some sign of acknowledgment, head tilted very slightly as he focuses entirely on this strange woman.