He said he would call her if he were dying, and for once he's true to his word.
"I'm sorry," that's all he manages to get out; then he speaks no more.
They trace his cellphone just in time, when paramedics find them he's barely alive.
Red John dies before they reach the hospital, while Jane's life is hanging on a thin thread.
Lisbon watches over him for three long days, until he wakes up with a smile.
She's barely able to fight back the tears as she leans forward and whispers a soft "I love you" into his ear.