This is simply Ais synchronizing her magic with her skill by using a trigger word instead of using them separately, Omori has also stated that Avengers synergy with Ariel is very bad.

When did Oomori said they have bad synergy?

Good question, probably from a Twitter post, but I don't remember much more than that. I think Omori has also made posts on the same subject for Bell & Alise.

As for the bad synergy, in typical Omori style it was a short sentance. so it is vague, I can't really say if it means Avengers & Ariel power combined aren't additive or that their backdraft increase exponentially.