1. 7.69s

Getting 7.69s is pretty easy.

Just press and hold the left and right keys at exactly the same time.

2. 7.68s / 7.65s

Getting a time faster than 7.69s is a little more difficult, but still easy.

You have to fall as soon as you start.

I hold down the left and right keys at almost the same time to fall quickly.

If you press them at the same time, you won't fall.

Immediately after falling, you need to press and hold the left and right keys at the same time

3. 7.62s

I tried 7.62s several times, but only got it once.

The moment the other NPC starts running coincides with the moment the player falls.

I believe this will be the fastest unless another strategy is discovered.