At the end of The Life and Death of Jeremy Bentham, when Ben first enters the room, he does everything in his power to stop John from killing himself. Why? Because Ben needs John to help him gather the Oceanic 6 and convince them to go back.
I think that Ben strongly felt he could recruit Jack, Hurley, Kate/Aarron, and Sayid, but always knew there was one person he could not personally convince to go back: SUN.
He knew that Sun blamed him for the death of Jin. He probably had people watch and even listen on her conversations with Widmore, and was fully aware that he had no way of being in the presence Sun, let alone convince her to go back.
That's why he needed John to help get Sun until this conversation happened:
Ben: I know we can do this, John. You haven't even been to Sun yet, let's start with her!
(Ben suggests Sun first so he can get the most difficult piece of the puzzle out of the way)
Locke: No, I promised Jin that I wouldn't bring her back.
(Ben's eyes go wild, the music gets dramatic and intense)
Ben: Jin, Is alive?
Locke: Yeah, but he didn't want her to know. He wanted me to tell her that his body washed up on the beach. He gave me his wedding ring to prove it"
Ben: Alright...a promise is a promise.
It's at this point that Ben is fully aware that he has something to bring Sun back. He no longer needs John. He takes off his coat. (Why would he take off his coat? People take off their coats when they're about to do something physical, like strangling someone) Ben walks over to the table and picks up the rope, as if he's taking it upon himself to roll it all back up, to help Locke clean up, but he's really preparing to sneak up on John and murder him.
I would take any suspicions that Ben was intrigued by Locke mentioning Hawking and throw it out the window, because at this point, Ben was already well on his way to killing Locke.
Locke begins to talk about Hawking, and Ben responds the same way a parent does when their 5-year-old child describes an event that happened in School, with fake interest and exaggerated responses. He shows little emotion or shock on his face when Locke begins to talk about Hawking, and before milking any more information, quickly kills Locke. If he was really interested in anything about Hawking, and Locke's relation to her, why wouldn't he ask more questions?
Ben needed Locke to get Sun, and now Ben could get Sun himself. With information of Jin being alive, she no longer had any reason to blame Ben.
Ben knew that Locke would really keep his word to Jin, and tell Sun that Jin is 100% confirmed dead, and would not only make it impossible to get her to go back, but would also put her murdering Ben her immediate priority.
Ben killed Locke to save himself from Sun.
Ben killed Locke to make sure Sun got on that plane, by telling her Jin is alive (even though Jin wants her to think he's dead). Theory by Mark
I think that Ben strongly felt he could recruit Jack, Hurley, Kate/Aarron, and Sayid, but always knew there was one person he could not personally convince to go back: SUN.
He knew that Sun blamed him for the death of Jin. He probably had people watch and even listen on her conversations with Widmore, and was fully aware that he had no way of being in the presence Sun, let alone convince her to go back.
That's why he needed John to help get Sun until this conversation happened:
Ben: I know we can do this, John. You haven't even been to Sun yet, let's start with her!
(Ben suggests Sun first so he can get the most difficult piece of the puzzle out of the way)
Locke: No, I promised Jin that I wouldn't bring her back.
(Ben's eyes go wild, the music gets dramatic and intense)
Ben: Jin, Is alive?
Locke: Yeah, but he didn't want her to know. He wanted me to tell her that his body washed up on the beach. He gave me his wedding ring to prove it"
Ben: Alright...a promise is a promise.
It's at this point that Ben is fully aware that he has something to bring Sun back. He no longer needs John. He takes off his coat. (Why would he take off his coat? People take off their coats when they're about to do something physical, like strangling someone) Ben walks over to the table and picks up the rope, as if he's taking it upon himself to roll it all back up, to help Locke clean up, but he's really preparing to sneak up on John and murder him.
I would take any suspicions that Ben was intrigued by Locke mentioning Hawking and throw it out the window, because at this point, Ben was already well on his way to killing Locke.
Locke begins to talk about Hawking, and Ben responds the same way a parent does when their 5-year-old child describes an event that happened in School, with fake interest and exaggerated responses. He shows little emotion or shock on his face when Locke begins to talk about Hawking, and before milking any more information, quickly kills Locke. If he was really interested in anything about Hawking, and Locke's relation to her, why wouldn't he ask more questions?
Ben needed Locke to get Sun, and now Ben could get Sun himself. With information of Jin being alive, she no longer had any reason to blame Ben.
Ben knew that Locke would really keep his word to Jin, and tell Sun that Jin is 100% confirmed dead, and would not only make it impossible to get her to go back, but would also put her murdering Ben her immediate priority.
Ben killed Locke to save himself from Sun.
Ben killed Locke to make sure Sun got on that plane, by telling her Jin is alive (even though Jin wants her to think he's dead). Theory by Mark