In essence she is waiting because of the noise her summons make, especially Nixie. In her mind, she wanted to possibly use the noise shock of Nixie against them once they're exposed, which I will consider.
Beatrice is in a position within striking range once the enemies are exposed. It was Ashley's opinion that sending the "buzzer girl" over now would be suicidal rather than a distraction.
[Ashley] look, we have initiative but to lure them into the trap we shouldn't pin them in, but you know, you guys do whatever. I'd like to see where we're at before I decide. Beatrice isn't exactly significant damage but might at least be a distraction. I'm still considering my options.
Round 0 she could have summoned or buffed Beatrice, and beause she didn't, I would allow a carry over into Round 1 as a reaction, though because she didn't explicitly state that, so instead if she acts before anyone else takes a turn then I'll allow it. Turn zero, everyone moved and performed an action except her so she can take her turn at any point as long as it occurs before she learns of any results from your turns in Round 1. It's fair that she learns what you were planning on doing as you all are in communication and strategic planning without her.