If you want to describe this scene in present tense (if it were happening now), here's a suggestion.

Why has everyone in the street run away? (Present perfect: has run away)

It's now the afternoon, and I am shopping in the street. All of a sudden, everyone runs away from me. In a few minutes, there's only one person left in the street, which is me. Why have all the people run away from me? I am confused. What's the reason?

Be very careful with using all - it's not as simple as it seems, and many learners make mistakes with it. As natives, we normally use everyone or everybody.

This sounds like you're telling a story, so you need to use the past tense. Try this:

In the afternoon [if it was today say "This afternoon"], I was shopping in the street. All of a sudden, everyone ran away from me. In a few minutes there was only one person left in the street: Me! Why did everybody run away from me? I'm confused. What was the reason?

[You might instead say "I WAS confused". Depends if you were confused at the time, or are confused now that you're telling the story]