[a@...]

That's just a TheoryCraft.

6 ling rush?
The zerg doesn't expect it to be successful b/c he already knows the protoss will just block the ramp with 2 zealots, hold positioned.
6 ling rush is just to keep protoss occupied in his base while zerg gets his natural and other starting positions.
It takes 2 shots of storms to kill a lurker, and how can P expand when he is stuck in his base defending like a crazy mofo.