Down a DPS and struggling to get through the add phases? Your decision was spot on. The people criticizing it in the moment are idiots. When the ninja didnt use the LB on the 2nd corona phase, your using it to speed up the subsequent add phase was 100% legit. Some people just get SO hung up on only using LB as a finisher that it breaks their tiny brains to see it intelligently used in any other way.

TL/dr? Dont stress, you did fine.