This is a key puzzle of the movie.

The only thing that they state in the movie is that it will be OK because "at least they'll get in the box" Friday 15:15. Thus we know that they intend not to create permanent doubles. So somehow they think there won't be a 08:45 Abe(2) exit. One possibility is that he's not thinking clearly. Another is that he has a plan that's not fully articulated on-screen.

I believe one approach me might be thinking of is the following. First, remember that he's been turning the box on at 17:00. That implies that each morning, he gets there at 08:00ish and finds it running. He must turn it off and then back on at 08:30. So, here's the theory: if Abe(0), after doing the punch plan and exiting the box at 17:00, writes a note and leaves it on the machine saying, "Don't turn this off and back on at 08:30; just let it keep running. Whenever you decide to get in, you will go back to 17:00 Thursday." (He could also add "Also, once you're back, at 02:00, stand in front of your house to keep some kid from setting off some car alarms." This would prevent the cycle from repeating.) When Abe(1) arrives at 08:00 to prepare for the day, he'll see the note. If he does what it says, then he won't do the off/on cycle. That means that Abe(2) can never exit at 08:45. Instead, whenever Abe(1) gets in, he'll go all the way back to 17:00, leaving Aaron(0) the only one left. When Abe(1) arrives at 17:00, he should rewrite the same note and in every iteration from then on, it's just an extra long day but not meaningfully different from an ordinary stock day.

This is a key puzzle of the movie.

The only thing that they state in the movie is that it will be OK because "at least they'll get in the box" Friday 15:15. Thus we know that they intend not to create permanent doubles. So somehow they think there won't be a 08:45 Abe(2) exit. One possibility is that he's not thinking clearly. Another is that he has a plan that's not fully articulated on-screen.

I believe one approach he might be considering is the following. First, remember that he's been turning the box on at 17:00. That implies that each morning, he gets there at 08:00ish and finds it running. He must turn it off and then back on at 08:30. So, here's the theory: if Abe(0), after doing the punch plan and exiting the box at 17:00, writes a note and leaves it on the machine saying, "Don't turn this off and back on at 08:30; just let it keep running. Whenever you decide to get in, you will go back to 17:00 Thursday." (He could also add "Also, once you're back, at 02:00, stand in front of your house to keep some kid from setting off some car alarms." This would prevent the cycle from repeating.) When Abe(1) arrives at 08:00 to prepare for the day, he'll see the note. If he does what it says, then he won't do the off/on cycle. That means that Abe(2) can never exit at 08:45. Instead, whenever Abe(1) gets in, he'll go all the way back to 17:00, leaving Aaron(0) the only one left. When Abe(1) arrives at 17:00, he should rewrite the same note and in every iteration from then on, it's just an extra long day but not meaningfully different from an ordinary stock day.