Pine is a really complex character and in the show it can be difficult to figure out how much of his involvement with different people is calculated, and how much is genuine.
My interpretation of Pine and Jed's story is that Pine was using Jed to get information about Roper, feeling guilty about it because that's how he got Sophie killed, and doing everything in his power to get her out of it alive. He NEEDED Jed to live and the fact that he was able to save her was important for him to feel redemption for Sophie. I don't think he could have continued to live with himself if he'd gotten Jed killed too.
I think Pine has a bit of White Knight syndrome. He has little identity outside of his mission. When a romantic/emotional interest fits into that mission he can feel very deeply for them and feels like he's responsible for them.
He ended up in that position with Teddy. This post isn't meant to debate whether his attachment to Teddy was romantic/sexual/brotherly etc.
I think we can all agree that he did the thing where he found someone loyal to Roper, cultivated emotional attachment of some type, and used that attachment to further the mission. That being said, I think he did get emotionally (in one way or another) invested in Teddy, particularly when he saw how broken Teddy was and how he chased after Roper's crumbs of affection.
He needed Teddy for the mission, but he still had that residual guilt about Sophie in the back of his mind. He needed Teddy to make it out alive.
While I really liked Teddy's character and wanted to see what they did with their dynamic, I'm fine with them killing him off, if they do something to address it with Pine later. If they don't bring it full circle and give Pine some internal redemption, then they're completely undoing the redemption he got with Jed, and we're back at the beginning, when he's being eaten up inside about Sophie's death.
Again, if you're making a sequel continue the story forward, don't undo what was done in the original work.