YOU SAID:

why would this do this and then stop doing it all of a sudden?

INTO JAPANESE

なぜこのこれを行うし、突然それをやって停止?

BACK INTO ENGLISH

Why do this, stop doing it abruptly?

INTO JAPANESE

理由は、突然それをやって停止?

BACK INTO ENGLISH

Why did it suddenly and stop?

INTO JAPANESE

なぜ突然やったし、停止するか。

BACK INTO ENGLISH

And why did it suddenly, stopping.

INTO JAPANESE

なぜ突然、停止します。

BACK INTO ENGLISH

Why suddenly stops.

INTO JAPANESE

なぜ突然停止します。

BACK INTO ENGLISH

Why suddenly stops.