Memento Revisited

(This post presupposes the reader's knowledge of the film Memento.)

Roughly half-way through the film, just past the chapter 6 marker on the DVD release, Leonard shows up at Natalie's house, agitated after a prolonged chase, fight and interrogation sequence with Dodd. She calms him down and almost immediately tells him that she, too, has lost someone, and will help him find this "Teddy." It is dusk outside. From there:

--Natalie undresses him and makes nicey-nice about Leonard's tattoos
--They ostensibly have sex
--She ostensibly drifts off and falls asleep on his chest
--He monologues her for a while about his condition and grief
--He walks straight to his clothes and finds Natalie's picture, and writes almost word-for-word what she said earlier, "She has lost someone too, she will help you out of pity."

By this point in the film, it is the middle of the night. Therefore an hour has passed, at the very least. Much more likely three to four hours have passed. By now the audience has seen him forget his circumstances in the middle of being chased by a stranger with a gun. We have seen him scammed into paying for two hotel rooms. We have seen him forget who he is talking to in a telephone conversation. So why does his memory -- which resets within minutes, even seconds -- last for several hours during this scene with Natalie?

The possible reasons are obvious:

1. He does not have a memory condition after all. It is simply a pretext and a cover to achieve other things.
2. He has a memory condition, but it is not nearly as bad as he lets on.
3. He has a memory condition, but he controls it as much as it controls him.
4. There is an error in the script.

The last one seems unlikely. My bet is on the first. Most interesting are # 1 and # 3, although most of you will probably opt for # 2. I hope to post more on the various inconsistencies in the film in the coming weeks.