IF CHRISTOPHER DID FLIP ON TONY:
I re-watched the beginning of the episode in which Chris dies. Within the context of him flipping after shooting J.T., here are some hints. Also, the wire would most likely be in his hat, just like the other guy's in Season 5 (and yes I'm aware he has a hat in both his 1st and last appearance).
The boy eating around Asbestos is warned about it. "What's that?" He was completely ignorant to the threat against his well-being that was right in front of him, just as Tony was ignorant to Chris' wire in the next scene.
The only thing Chris mentions at the Leotardo meet is that there is "monitoring at every landfill". The wire is on his mind. He also seems cold, on edge, and distracted (could be due to the drugs, or both).
On the ride back, Chris mentions a person and specific landfill by name. Tony falls for it and confirms (busted).
Chris changes the station too many times, just like he always changes his mind. Tony comments on this.
Chris then begins to look visibly shaken, and turns up the volume (to drown out the wire?) His face is noticeably moved, emotional, to the point even Tony becomes suspicious of him.
The van then flips (as the original poster mentioned, it's a metaphor for Chris flipping). It flips downhill, and then right when you think it's about to land, it actually flips some more.
What the original poster of this topic caught on to, is that Chris is concerned with his drug test more than anything else because he thinks he will lose his deal with the Feds.
And Finally, when Tony is being wheeled into the hospital they ask him for Chris' next of kin. He thinks about it and says... "His wife". The scene cuts to a close-up laptop screen with TOP 10 MARKETS WHERE TO BUY: PANAMA CITY, FLORIDA. (Chris was going to leave New Jersey and get away?)
Re: Chris flipped on Tony before death?
2We'll never know if the frenchman killed by Bobby was in fact Harpo. In this series, not everything is proven. But it could still be the case. That's the art of it.