Out in the lot, Walt plays the dropped-keys bit and retrieves the tracker that he bought and placed on Jesse's car LIKE A TOTAL JERK. At home, he checks Jesse's whereabouts yesterday. As Walt traces the route from Jesse's house to Gus's house, Jesse leaves a message on Walt's voice mail; he really needs to talk to him.
So Walt comes over -- the first time in a while he's arrived at Jesse's house without having to frantically ring the bell or bust the door down. Inside, we see the house is really returning to form. A futon, Jesse! Very good. There are still speakers up on tripods, like Jesse still wants to throw bumping dance parties, but also: curtains! Jesse gets right to the point: "they" want him to go down to Mexico. He's so nervous, you guys. He explains everything he's been told about Gus's war with the cartel and how they've been attacking Gus's operations. Walt, at his low level, knows about none of this, which has to make him even angrier. So between the cartel and Hank, Gus's hand has been forced; the cartel wants half of Gus's operation and Walt's formula. ...Okay, time out: no. I don't buy that Gus would do that. I don't at all think we have the full scope of what Gus's plans are. Half of the business PLUS Heisenberg? No. But anyway, Jesse says that "they" want him to go to Mexico and train the cartel workers how to make the blue stuff. Sounds foolproof. "Gus doesn't trust you," Jesse sums up, "so I gotta go."
Jesse is so freaked. More than anything else, he wants Walt to guide him. He's no chemist! He doesn't know! What if the instructions on the equipment are written in Mexican? Replace all the meth/chemistry/Mexico particulars in this scene and imagine yourself talking to your dad/mom/mentor about some scary job you've been offered where you're not sure you can do it. That's all Jesse wants here. He wants Mr. White to tell him he'll be fine and he'll be there for him if he has questions. He wants support. He finally says it out loud, to his credit: "Coach me. Give me some notes." But Walt's no longer interested in providing support. And why? Because Jesse won't commit a second murder for him.
"So you saw Gus?" Walt accuses. Jesse denies it, saying the order was "passed down" by "Mike and them." In the span of three seconds, Walt asks Jesse about seven times to clarify that he has neither seen nor spoken to Gus. "You weren't at Gus's house last night?" Jesse sputters. Walt forcibly grabs Jesse's cigs, sees the ricin is still there. He demands that Jesse look him in the eye and tell him. Jesse says he didn't have a chance to dose him. One big pot of stew, man! "What was I supposed to do, huh? Poison myself?" No, sweet boy, Walt had you do that last season. Walt calls him a lying little shit; he only had ONE thing to do, and after two hours and eighteen minutes in Gus's house, he still "didn't have the guts" to do it. Jesse, again not an idiot, catches the "two hours, eighteen minutes" thing; how did Walt know? Walt pulls out the tracker, all proud and badass. He again accuses Jesse of having "no intention" of killing Gus, while at the same time Jesse fumes about Walt spying on him, especially after "everything I have done for you..." "Everything you've done for me?!" Walt snaps. "You've killed me! You signed my death warrant!" Oh, if only. Imagine Jesse hearing this from Walt, not a day after he laid his body down on train tracks for Mr. White. Walt continues ranting: Jesse wants some advice? Sure thing: "Go to Mexico and screw up like I know you will. And wind up in a barrel somewhere!" At this, Jesse whips the tracker at Walt's face, hitting him just above the eyebrow. HURT HIM, JESSE!