"My ship don't crash. If she crashes, you crashed her!" She ignores him, because blustering is his main hobby. Simon approaches from behind, and Mal reminds him that River will be accompanying them on the job once they land, should they not explode and die. There's another crash and shake, and Simon looks nervous. "Fear is nothing to be ashamed of, Doctor." Simon explains that it is not fear, but anger that he is feeling. Mal says it's hard to tell, and Simon gives him a snippy over-explanation in reply: "Well, I imagine if it were fear, my eyes would be wider." Mal says he'll look out for that next time, knowing full well that Simon's wrong: it's fear. "You're not taking her," says Simon, and somewhere in this beat of the scene there's a cut because of the set constraints -- the camera has to get all the way around Simon to follow them down through the ship, and can't. But you wouldn't notice, so it doesn't count -- the point of the tracking shot is not affected, and the continuity of the ship exploration is not interrupted. The movie's named after her; it's important we get to know her and the people inside as efficiently and engagingly as possible.
Simon follows Mal through the ship, bitching at him. Mal ignores him until he's forced to suddenly whip around on him: "I hear the words 'that's final' come out your mouth ever again, they truly will be. This boat is my home. You all are guests on it." Simon continues to bitch about how he's more than a guest; as ship doctor, he's earned his passage. Dumb move. "...And it's time your little sister learned from your example." They get down a stairway into the lounge (most memorably visited by River when she saw Simon and Kaylee canoodling in "Objects In Space") as Simon points out that this work usually involves "bullet holes, knife wounds, laser burns" from the kinds of jobs Mal means to take River on now. Mal explains that mentally traumatized 17-year-old or not, she's still psychic, and they need protection and foreknowledge on this trip. He does not yet know that she is also a crazy ninja, because nobody knows that yet. In the med lab, one of my favorite sets, they continue bitching as Mal rolls up his sleeve and Simon injects him with something. It's a wonderful note on the scene, the way they're at each other's throats and still so intimate that their physical routine isn't interrupted in the slightest. It makes the point that no matter how much they complain, Simon's still crew, and no matter how bad Mal's decisions, he's still a patient, and they are family. Simon criticizes Mal for his economics of utility, and Mal comforts him: "Honestly, Doctor, I think we may really crash this time anyway."
Simon whinges about how hard he worked to get his sister away from the Alliance, and Mal sneakily threatens him: "I [know], and it's a fact we here have been courteous enough to keep to our own selves. I look out for me and mine. That don't include you less I conjure it does. You stuck a thorn in the Alliance's paw. That tickles me a bit, but it also means I got to step twice as fast to avoid them, and that means turning down plenty of jobs. Even honest ones. Put this crew together with the promise of work, which the Alliance makes harder every year." It's a matter of whether the Tams as part of the family really weigh off against the fact that they endanger the group as a whole, and it's a very dark train of thought that Mal's never really considered this seriously before, even hypothetically. He's thrown them off the ship plenty of times, but he always comes back. "Come a day there won't be room for naughty men like us to slip about at all. This job goes south, there well may not be another. So here is us, on the raggedy edge." He gets right up in Simon's face: "Don't push me, and I won't push you." He stalks off, cursing in Mandarin, and the camera follows Simon up the catwalk, to where River's been listening since they reached the hangar bay. Below, Zoe and Mal continue to discuss whether her husband is going to end up killing them all in a minute or two. "Like a downy feather, sir. No one flies like my mister." Simon kneels at River's side and touches her back. "I know. We're going for a ride." The shot finally cuts. That was awesome!