With respect, we have seen Ortegas trigger happy all season. Even in the fantasy episode, Ortegas is the one most interested in skewering people with a sword.
With even more respect, ignoring the fantasy episode (as the characters were not themselves we can't use it as a frame of reference, hehe or else L'ann is going to look very different), while Ortegas has sometimes been assertive and even aggressive, she's never really been trigger happy, and never been belligerent to the point where the captain had to have her stand down. In fact, there have been scenes where she was the reluctant one, often double checking the captain's orders (are you sure you want to go in there) kind of thing.
There was clear anger in this episode we had not seen before. Now I'm not saying its unjustified, it just felt a little off compared to episodes before, we have never seen her get to that point, and I never really understood why. Was she just so distraught and angry about losing the starbases (which would be very understandable), was there some backstory there with Romulans we are unaware of? Is it simply that older Ortegas is an angrier, more belligerent person?
There are several reasons to explain why Ortegas might be angry, again I would never say it wasn't justified, I just wanted to understand better what was driving her character.