Well, because if you don't remember having done something you are not okay with then you don't feel guilt. Although I would say that's not necessarily true. Some character could get blackout drunk and beat the snot out of his friend and then realize the next day what he's done. He doesn't remember it, but he'd still prolly feel guilty.
The question becomes can you feel guilt over something you are doing, or are going to do. I'm thinking in this case of Dom from Fast 8, does he feel guilty for "appearing" to turn on the team? Maybe but the stake of the safety of his son is a higher priority than the guilt/betrayal.