I was using technique i was told was safe way on internet, a few years ago. Halve it, then stick knife in our to remove. As I pulled knife from pit, it slipped and I needed stitches.
Person stitching me said avocados are huge reason for ER visit. So I asked her safe technique. She didn't know .

I was gifted an avocado pitter after this incident, and highly recommend it, or just use spoon to pit.