Once again, I don't think it's clear yet which tribe is going to TC, so it's best to look at both. Who is going to RI from each tribe is a little more clear, however.

For Coachtribe, I think Edna is clearly the one to go home if they go to TC again. We see in the previews that the tribe at least makes a show of coming together and bonding after the contentious vote last episode, so presumably they see value in holding together. Edna is the lowest person on the totem pole and should be an easy vote if they lose the IC again.

There is one wrinkle to all of this, which I'll mention at the end.

At NotOzzytribe, Ozzy is clearly on the outs despite his lame attempt at getting his tribe to forgive his stupidity. And we see him in the previews offering to go to RI. It's a no brainer - if someone offers to go, everyone else's sense of self preservation says "Sure, man, go for it!"

So yeah, Edna for Coachtribe and Ozzy for NotOzzytribe. But of course, Probst wants to keep us guessing so he threw this out in the EW article:

EW: We’re almost halfway through the season, so hit us up with an extra-special tease for next week.

PROBST: Extra special? Okay. Part 1: It’s time for some Coach-chi. Part 2: An epic blunder in a challenge may cost a favorite their spot in the game.

So does someone totally screw up at the challenge and get themselves booted? This feels more like something that would happen at Coachtribe.