The Shaman had RED latency at the timestamp you linked. You can’t batch together two spells while clicking and having 800 ping.
Patch 2.3.0 (2007-11-13): Elemental Mastery: It is no longer possible to get two consecutive guaranteed critical strikes from using this ability.
This is the guy that wrote Shaman guides and had his topics stickied back in Vanilla. I think he knows what he’s talking about.
https://web.archive.org/web/20060503155601/http://forums.worldofwarcraft.com/thread.aspx?fn=wow-shaman&t=36840&p=1&tmp=1#post36840