See how Jackson puts his arms up, nods his head slightly, and closes his eyes? He understands what Derek has to do to stop him. He knew he had to die to protect Lydia and the others. He just knew. In a way, it shows the side of Jackson no one but Lydia (and probably Danny) knows. It shows him being selfless for once. Not a cold-hearted douchebag like usual. Later, when he awakens and hugs Lydia you can see the shock in his eyes at being alive. He didn’t go into this knowing he’d live, he went into this thinking he’d die. Little things like this just keep showing me why I love Jackson and why he’s much more than a pretty face.