There are 2 reasons to use Emergency Tactics:

1.) When AOE damage is taken, and players are not in danger of taking damage in the next 30 seconds. Using it with Succor here allows that Shield damage to be converted to HP instead of falling off.
2.) When trying to get a tank up quickly from low HP and using back to back Adlos. Since shield don't stack, using Emergency Tactics here on the second Adlo allows max effective life per GCD.