[Grammar] while/as/when

[contiluo]

I'm confused by the use of following sentences. Which is correct?

1. Unexpectedly, my shorts split. I was screaming out while squatting down.
2. Unexpectedly, my shorts split. I was screaming out and squatting down.
3. Unexpectedly, my shorts split. I screamed out as I squatted down.
4. Unexpectedly, my shorts split. I was screaming out when I squatting down.

 

[Tdol]

I think the third is best. I would probably use cried out, though. The past progressive doesn't work for me.