I loved this detail right here, where Percy is so enraged to see the Briarwoods that his glass shatters in his grip.
And then a few minutes later, you see blood seeping into his glove from the broken glass, meaning he never unclenched his hands.
A great example of show-don't-tell. He's so incredibly angry at this whole situation that he either didn't notice the broken glass cutting into his hand, or he just didn't care.