If it was Carson Dial who killed Charles Lambert what was the motive? Obviously it wasn't the money, since killing him didn't get him the money.
Play the game existence 'til the end...of the beginning...
Carson Dyle's motives for killing Charles, Tex, Gideon and Herman were twofold; first there's revenge, which Dyle talked about in one of his last scenes (the one in the Colonnade) -CARSON DYLE: ...It takes a lot of bullets to kill me. They left me there with five of them in my legs and my stomach, Mrs. Lampert; they knew I was still alive but they left me there. I spent ten months in a German prison camp with nothing to stop the pain. They left me there, Mrs. Lampert, they deserved to die!...They knew I was still alive but they left me there. That's why I had to kill them, all four of them.
Second, Dyle wanted to make sure he didn't have to share the money with anyone; as Regina correctly observed, "He wants it all."
Dyle was planning to kill Charles whether he got the money from him or not; when he discovered Charles didn't have the loot (or so he thought), he turned his attention to Regina.
...actually, he did have both motives you mentioned - yet he didn't have to have them in order to kill him. Lampert's death might very well have been "coincidental" : an accident for example (during some fight they probably had on that train, while Dyle was trying or intending to make Lampert spill the beans considering the whereabouts of the money. If Lampert saw Dyle, he immediately knew he had to kill him or be killed).
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