Yewll was giving Nicky a checkup -- her arm and leg were acting up, aching -- but it wasn't the kind you give a human, because Nicky Riordan is secretly not a human: She's one of the human-model Indogenes (Indosapients?), like Gordon McClintock, only fully aware of her realities and presumably not a Manchurian Candidate-type sleeper assassin. Still, given the Kaziri and the stuff we see her do later, it's pretty clearly a big deal.
So when Hunter Bell walked in to beg some medical supplies, spotted her, immediately turned around and left, it wasn't just about sneaky plans and secrets: It was about Yewll and Nicky, at the very least, being exposed as too dangerous and sketchy to deal with. So they wrapped things up and headed to the Need/Want, at which point things got dicey.
Hunter Bell: "The fuck, though? Jered, go get us some drinks."
Yewll: "Nicolette, be circumspect..."
Nicky: "Like he's going to live through this, fuck it. I'm an Indogene, camouflaged biologically to appear human."
Hunter Bell: "Like a spy?"
Nicky: "Kind of. There's something very important in this town, which in the wrong hands could prove dangerous. We're here to prevent that, we're here to protect Earth."
Hunter Bell: "For my kind, or yours."
Nicky: "All kinds."
Hunter Bell: "Sounds very heroic. I'm inspired. So a hundred grand and we'll call it even."
Nicky: "Or else I can just go ahead and kill you."
Yewll: "Holy Moses! You just went ahead and killed him!"
(Jered appears with their drinks.)
Nicky: "Yeah, that worked out well. I thought maybe I didn't club him hard enough. Jered dear. would you mind helping us clean up this mess?"
Jered: "Sure, because I'm a Liberata."
Nicky: "So see? Everything's fine. Datak's been framed, Jered is dead. It's perfect."
Yewll: "Riiiight. Okay, here's how this is going to go. I'm administering a paralytic to you first, so you won't fight back but more importantly so you won't feel pain when I stick in the second needle, which is what will actually kill you. While all of this is going down, I will say my farewells."
"When I first came to this town, I wanted to start over, I wanted to right my wrongs. And you told me everything that I wanted to hear, you were my inspiration. But you changed. You unleashed the Volge, Nicky. You murdered a harmless bartender. It has become painfully clear to me that there is no end to the lives that you're willing to sacrifice for what you call the greater good. If I can't trust you with a simple walking stick, how am I supposed to trust you with a genocidal weapon? Because I've changed too. I've become a healer instead of a destroyer. And that's why I'm so sorry for this, for what I have to do, but it's for the greater good. I love you. Goodbye."