It was a ludicrous scene on many levels and not even close to anything in the book. And unnecessary if the goal was give Rhaenys a badass moment because..well, book scenes.
Overall, I didn't care for the episode. Just all over the place and also boring. A search for Aegon that felt like unnecessary padding. The silly "accidental" death of Beesbury, accidental deaths just like that aren't realistic (however Commander Cole slashing his throat in the book seemed the most likely, and would have highlighted how tense and murderously premeditated this whole fateful council meeting really was, not the weird improvised clusterf*** we saw).
The deviations from the book are fine until they become so silly and unrealistic and greatly undermine the book characters and events. Book Otto never wanted to kill Rhaenyra at the outset or drastically attempt to escalate anything, he concealed the king's death to crown Aegon yes, but actually tried then to somewhat (since he didn't have a death wish) to avoid war via deals/diplomacy (much like a later Hand Tywin Lannister probably would have).
The show would have us believe the maesters' recording of history is so wrong and incompetent that they got it wrong that Kingsguard Lord Commander Harrold Westerling died 20 years before King Viserys. Cole was supposed to be Lord Commander long before this episode, he's supposed to be a seasoned leading influential figure right now (not in the future), kinda like a corrupt police chief.