If Tyriel hadn't decided to act incredibly creepily/ in an almost stalker like manor, then asking to speak to Ciella privately and apologising would have been the correct move. She shouldn't have expected to things to back to the way they were, but at least they might have been able to start over amicably. Despite the situations face value, she kind of did Ciella a favour by giving a her reason to break up with her fiancé (which is what she had always wanted anyway).
But no, she had act in the way that makes it seem like to she has lost her mind just to create drama. She has swiftly gone from a naïve and flawed, but potentially redeemable character, to a wild card, backed into a corner with nothing to lose.
What a disappointing turn of events.