Thats nasty.
Forgive me for not trying to get a look at the pictures in more detail, im a tad squeamish.
How it getting on this far down the track??
Im with you redeye, 9" grinders ar something i treat with upmost respect.
I have a 5" makita and i was cutting the bulkhead out of a HQ, through the windscreen pillars and through the floor under the seat. To get into the 90 deg at the back of the sill i removed the guard. I put my hand up to shield my eyes from the sparks and put my little finger onto the disc. It didnt bleed a bit, it did cut fairly deep, no need for stitches or anything. Took a while to heal.