Emergency Tactics should include instant cast

[Slark]

Nice on paper, but I don't think that works as well. What works well is ET Adlo > Adlo, or ET Succor > Succor. But Adlo > ET Adlo > Adlo...
By the time ET's animation is over in your second Adlo/Succor, you've easily wasted there an entire second of GCD...might as well just Adlo > Physick.

I don't know what kind of internet or computer you're playing on, but I literally have zero delay between heal > ET heal > heal, and its been extremely helpful on dungeon rushes and a4.

Adloquium is a base of 2 seconds. GCD is a base of 2.5 seconds, meaning there is .5 seconds where you have nothing to do. If you cast ET during that timeframe, there's absolutely zero delay if you are playing on a computer that isn't lagging (me).

ET is not on the GCD, so it cannot "waste an entire second of GCD." Not really sure what you mean by this.

Cast Adlo > Lustrate > Adlo on yourself, and you will run into a period where you cannot cast the second adloquium for a short time because you're sitting in Lustrate's animation restriction, because lustrate's animation restriction is approximately 1-1.25 seconds long.
Emergency Tactics' animation restriction is incredibly short; its approximately .3-.5 seconds long.
Cast Adlo > ET Adlo, and you should not experience delay between adloquiums if you have a decent computer.

If you arent sure what an animation restriction is, or don't believe that some spells/skills have different restrictions, go use healer LB3 and sit there for 15 hours to get an idea.