Why does the negative speak twice in a row in the middle of the debate?
The negative speaks twice in part to equalize any competitive advantages that the affirmative may have in speaking first and last. Also, this structure is required in order to allow the affirmative to speak last. This structure allows the negative to develop their arguments in depth, which is important because the affirmative got to choose the ground of the debate in their first speech. Strategically the negative should use this opportunity to make as many points against the affirmative as possible, and to maximize the time crunch the first affirmative rebuttal will have in the next speech.