How does Lee create suspense at the end of this chapter? What does Ewell's comment foreshadow?

Ewell's comment about one down and about two more to go foreshadows that this horrible time of racial prejudice and discrimination will not end as long as men like Ewell are around. He will make sure that everyone who has harmed him will dies.

"One down, two to go." This foreshadows his attempts on the Finches' lives.