To get the plastic broken piece out of the one blade you must take it apart. So similar to replacing the servo motor you have to pull the bottom piece of the oneblade off.
Then remove the power button casing but be careful because the plastic at the top attaches to the body where the razor gets put in, so the casing is where the power button sits. Once you take that off you will see lube to the servo. You will see where the blade connects into the plastic housing. If you have a toothpick or something small you can try to push it through the plastic at the bottom as it is very thin and push the broken plastic piece out. May take a few tries but it will work.
I did mine in 10 minutes so it's not too bad
Thank you for reading hope this helped.