From Daily Dose of Hebrew website. We are told that the symmetry is even more awesome in Hebrew. The threefold repetition of Tarshish emphasises that Jonah is seeking to go away from the presence of the LORD. All the while Jonah is descending, eventually into the depth of the sea.
A. But Jonah rose up to flee unto Tarshish from the presence of the LORD ,
B. and went down to Joppa;
C. and he found a ship going to Tarshish: so he paid the fare thereof,
B’. and went down into it,
A’. to go with them unto Tarshish from the presence of the LORD.