If the clip's audio and video are linked they will stay in sync when edits are made.
If a clip is unlinked, select the tracks and right-click on one. GROUP them.
A clip on the timeline can be right-clicked, then SHOW ORIGINAL CLIP chosen. This will highlight the source clip in the Bin.
Save Project File AS routinely, giving it a unique # or name, so as not to overwrite prior saves. Using Save Project Files (no AS) will overwrite. Then, if things go away, you can step back to an earlier edit just by clicking the appropriate VPJ file.