8. (15 points) The seven members of the Running Family need to complete the challenge by passing through 7 doors in the figure; the first person can choose any door to activate, and after completing the challenge, it will activate the adjacent doors on both sides; the next person can choose any unchallenged door from the activated doors, and after completing the challenge, it will activate the unactivated adjacent doors on both sides; and so on. In the end, all seven members of the Running Family completed the challenge. Sorting the numbers of the seven doors according to the order they were challenged will result in a seven-digit number, and there are $\qquad$ different possible seven-digit numbers.
【Answer】Solution: According to the problem, each choice situation must correspond to a seven-digit number. After the first person makes a choice, the next six people only need to choose "left" or "right". The door chosen by the first person can be completely deduced from the total situation of the next six people's "left" and "right" choices. That is, each of the next six people has two choices. Therefore, arranging the numbers of the seven doors in the order of their challenges will result in a seven-digit number, which has a total of $2^{6}=64$ different possibilities. Therefore, the answer is 64.