on the handle item no. 10?
If not, the pull rod no. 11 might be broken. There is a screw in front of the selector lever handle (no. 12). Unscrew this, and then you can pull out the handle with the pull rod.
That happens very rarely, just if someone is pushing the handle very strong w/o pulling the trigger when switching to reverse or similar.
see here the details.
The key should go out. Try is smoothly and push it correctly till the end into the key hole.