When we rejoin Sam and Bobby in Purgatory, they've already hashed out much of the exposition off-screen. I'll give the writers credit for that much, at least. Bobby has been assuming that Sam is bringing him back to Earth, and looks forward to helping the boys again, so Sam has to remind him he has no earthly remains to which he can be anchored. He also explains that he has to see Bobby off to Heaven in order to finish the second trial. "Well, I'll do my part," Bobby sighs, "but I ain't exactly the retirin' type, so you idjits figure out a way to spring me." Sam absently promises they'll do just that, but he's more concerned with the fact that they've just walked into the predetermined meeting site and Ajay is nowhere to be seen. "What if he doesn't show?" Bobby asks. "We got no way out," Sam says. Or he could go look for the escape hatch that Dean used. But, you know, whatever.
It's daytime by the time Benny gets to the alleyway. Wouldn't it have made more sense to meet each other halfway if time was of the essence? Maybe Benny was just hanging out in the next town over. Dean has already explained the situation to Benny and finishes by saying, "You want nothing to do with this, I'll completely understand." Benny lets out a low whistle. "Dean Winchester asks for a favor, he's not screwing around," he says. Has Dean just asked him to run away with him so they can fight crime and come up with funny portmanteaux together now that Sam is finally out of the way? Sadly, no. Instead, he has asked Benny to fetch the tall grumpy one from Purgatory. "Sending you back there is the last thing I ever wanted to do," Dean says, "but my little brother's stuck down there." Benny remembers Sam as the guy who wants to kill him. Dean tearfully admits he hasn't been there for Benny lately. He says he's asking too much from Benny, but Benny isn't turning him down: "Come on, Dean, you know I love a sandwich."
Hold on. That can't be right. Let me check the CC.
Ah, here we go: "Come on, Dean, you know I love a challenge." Is there a better friend than Benny in the whole world? No, there is not. "I owe you," Dean says. "You don't owe me nothin'," Benny says. "Truth is, I could use a break from all this." He doesn't fit in with humans or other vampires, he says. "I don't belong. After a while, that starts to wear on you." Benny laughs off the tears that are about to start welling up. "Like you need to listen to this!" Not only is he willing to be beheaded in the name of friendship, but he doesn't want to burden Dean with his problems. Dean tells him to hitch a ride out of Purgatory with Sam, not accounting for the possibility that Sam would still be a jerk to Benny. "As soon as I send you back," Dean says, "I'm gonna haul my ass back to Maine, and I'm gonna be waitin' there when you get topside." Benny nods and agrees to the plan, but it's entirely for Dean's sake. You don't talk about life being too hard if you plan to come back to it, regardless of what plans your friend makes.