This refers to the audience by their "hearts." "The terror" refers to their war with the Assyrians. This can be stated clearly. Alternate translation: "You will remember the terror that the Assyrians caused you when they attacked" (See: [[rc://en/ta/man/translate/figs-synecdoche]] and [[rc://en/ta/man/translate/figs-explicit]])
These rhetorical question are asked to emphasize that the Assyrian officials are gone. These questions may be written as statements. Alternate translation: "The officers of Assyria who counted the tax money that we were forced to pay to them have disappeared! Those men who counted our towers are gone!" (See: [[rc://en/ta/man/translate/figs-rquestion]])