They held hands.
While Percy had Frank and Hazel leaning on his shoulders just a few moments ago, he was eventually called up to be with Reyna at the front as praetors. He said his goodbyes and see you laters, and while he was sad to leave them alone, he was a little bit relieved. This was a moment that, even though he wanted to share it, he felt he had to be alone for it. Or at least, had someone who understood what he was feeling, with him.
He only glad that Reyna did. He always did hate being by himself.
Reyna reached for his hand as soon as he got there. Percy didn't expect it, but he wasn't all that surprised either. He saw the worry lines appear on her face far too many times, he saw the way her lips slightly quivered whenever she dared say Jason's name. But that wasn't what gave her away. He knew what people looked like when they were trying to be strong. That was how he felt when he read the First Great Prophecy, anyway.
He whispered, "Okay?"
Reyna looked at him, set her eyes forward, and said, "I'll be alright."