First UNlink all A/V in the track.
Lock the audio track.
Choose the insertion point and create a single video-track split there.
Right-click the new image in the media bin and a menu appears.
Choose "place on sequence." Another menu appears.
Choose "place cursor on new track." The new item will appear just above the next lower-numbered track.
Place the pointer within the original clip (below the new clip) while holding down <alt>...
Drag it to the right, to the end of the new clip (visible on the track just above). The original clip should snap into place where the new clip ends.
Drag the insert track into the hole created by the original material, if you wish.
Result is a video insertion that has no effect on audio. The original video resumes where it left off prior to the insertion.