Emma: Come on, Henry. I know you want to believe the answer to everything is in Operation Cobra.
Henry: It is!
Emma: Sometimes, the real world needs to come first.
Henry begs Emma to try one more. He picks out a key and tells her to use it. Emma's eyes grow wide when they fit in the lock. She looks in wonder as the door swings open.
Henry: Do you believe now?
Enchanted Forest, Night. Snow has Charming tied to a tree. She assumes he's the man Rumpy helped her forget and mocks him, when he tells her his name is Charming. Charming can't figure out why true love's kiss didn't restore her memory. Snow says it's not true love because she doesn't love him. Charming insists she does; she just doesn't remember. Snow isn't interested in words. She's a woman of action. Taking action is exactly what she's going to do. Charming tells her she can't kill Queenie. It's not who she wants to be. Snow tells him to watch her.
Sawyer: Baby, he is tied to a tree in the jungle of mystery.
Storybrooke, Archie's office. Archie hypnotizes David and asks him to remember the last time he spoke to Kathryn. David says that on the night Kathryn disappeared, he called her on his cell phone. She said she needed to start a new life without him. She thought he and Mary Margaret should be together. While Kathryn said she was hurt, she also said she wanted David to be happy. Archie asks if anything happened after that. David says he saw Mary Margaret in the woods. Archie asks what she was doing there.
Hypno-Flashback -- not to Storybrooke, but to the Enchanted Forest. David hears his own voice, but of course it's Charming, saying, "You can't kill her." He sees Snow (long hair, costume and all), who says, "Really? Watch me." Charming says, "Don't do it."
Archie shakes David awake and tells him he was going too deep into hypnosis. Archie tells David something was disturbing him and asks what he saw. David stammers but doesn't answer. Instead, he flees from Archie's office, even though Archie insists he can help him.
Sidebar: David's already on The List because of his adultery and his inability to man up and be honest, so there's a lot of anger in the fandom that David didn't take notice of Mary Margaret's long hair or costume, in his hypnosis recalled memory. I think, had he been willing to talk to Archie, Archie might have known enough to ask questions that would have helped David figure out this memory couldn't be of a conversation with Mary about killing Kathryn. I also think, though, that it's understandable David doesn't think these details are all that important. I know when I dream, there are often differences in people and places. What's more, we know about the two worlds; David does not. He would have no reason to think that a conversation between his voice and Mary's face was actually between their true identities, because he thinks this is his true identity. In short, I think it's fine that he panicked and fled. Poor noodle is trying.