Under normal conditions, being swept up by a Time Storm would result in appearing in an unknown time or the future, forever rejected by time and unable to return to one's original space-time.
This was also the reason for the Time Dragon's panic at the time.
Jack Clark could return because he had the Destruction Emperor Dragon, which was part of him, anchoring and locking down to the original time period, and with the aid of the Hell Coordinate, he leaped back.
Otherwise, even with the Hell Coordinate, he wouldn't be able to accurately lock onto the time to jump back to.
If the jump was incorrect, appearing in a time period before he was caught in the Space-Time Chaos, the simultaneous existence of two 'Jack Clarks' would instantly trigger a local space-time confusion.
Then he would be completely devoured by time and never able to return.