Zash is feeling inordinately pleased right now, and even a bit smug, though he recognises being smug about being part of a species that has a certain kind of telepathy is a little bit silly. It'd be like being smug for having toes. ......well, he made his toes, plants don't have them and he didn't have them when he was born, but still, you get the picture.
Now going back to another thing Siran thought—Zash wants to contrast the way Siran feels about thrill and about power with the way he himself does. He doesn't know that much about the way Siran does it but he felt like there was something there they could look at, and maybe they can just show each other themselves and then contrast? He'll go first.
There is a thrill and a power there, Siran is absolutely right. Zash doesn't often focus on it or lean into it but it's... it's a bit like...
Side comparison: it's a little bit like his hair. His ridiculous fluffy bright-yellow hair, which is so attention-grabbing, and which coordinates with his orange shades and his red jacket and his boots and his gun. He feels a bit embarrassed to admit this but he is an aesthete. He's a little bit vain. There's a certain aesthetic that he plays up, plays into, embodies. He's an incredibly skilled gunslinger, he can literally shoot a single wing off a wormfly from fifty yards away, and he loves the aesthetic of using that skill to never, ever kill anyone. To, in fact, prevent people from being killed. He understands that his pacifism comes from a position of privilege, that he can afford to be pacifistic because if he decides a conflict isn't happening then it doesn't happen full stop. That's part of why he doesn't, really, judge others for not being as pacifistic as he is, doesn't demand it of them.
And that, of course, circles back to the power thing. He is incredibly powerful. He is incredibly skilled, and deadly if he wants to be (which he never does). And there is a thrill there, there's an ego thing there. He is that person, that powerful superhuman creature who could kill dozens of people a second and who instead chooses not to, and chooses to help them. The ego thing and the power thing and the thrill thing aren't the reason why he does this but they do help.
And there's another thing that attaches to the tail of that: much of his power and skill was earned. He was nowhere near this good, a century and a half ago. And... people suffered because of it, people died. The central motivation here, of not wanting people to die, that core is probably unshared between him and Siran, but here, Zash can show him how everything else he is fits around that one thing like a jigsaw puzzle. He cultivated his skill and his power and his image around that core, and he became better, and stronger.