Yes, I do get your meaning, but I think Dean would rather leave a mostly capable Sam to his own devices, than to have to stick around, and either TELL Sam the truth or wait for Sam to find out (either of which would give Dean a heart attack), and then face the music. He doesn't want to face the music, so in his mind (his poor, wrecked mind) what he's doing is the latter of two evils.....yeah?
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