Healer pulling?

[DeaconMoore]

My raid leader, also a healer main, said it was excusable, since it was in anticipation of healing a tank.

So what's the issue here? From your description of the situation it sounds like a pull was about to happen but was aborted after the ast dropped the spell. You can't undrop it. What was done was done. As they say, $#!+ happens.