disconnect the source from the audio track. Next to the green audio buttons, you’ll see two connected icons that will say a1 and A1. click a1. it should move a little to the left. Repeat for track 2. now drop your broll on the timeline, and no audio will come with it.
To expand on the principle. if you drag a1 to A3, and a2 to A4, when you place your clip on the timeline, the audio will land on A3 and A4.