You can remove the audio from the Timeline by navigating frame-wise. You can navigate frame-wise by using the Next frame and Previous Frame button in the Preview window. It is best to zoom in to the Tmeline for accurate frame editing. To remove audio from a section of the timeline.
1. On the View menu, click Selection Sliders or use the F5 shortcut key.
2. Select the portion of the Tmeline by dragging the sliders.
3. Lock or Unlink all tracks other than the audio track.
4. On the Edit menu, click Delete or use the Del shortcut key.
A better method is to use Volume Tracks. Volume Tracks enable you to change volume of an audio track at any point of time.
1. Click the small plus sign to the left of the audio track to display the Volume Track.
2. Click at the point of time from where you don't want the audio.
3. Drag the Volume Point that appears to 0 Volume.
4. Click at the point of time up to where you don't want the audio.
5. Drag the Volume Point that appears to 0 Volume.