AmIWrong?

I was working the dementia hall at our facility when resident was readmitted to our facility from a behavior unit. This resident has a history of hitting other residents and was repeatedly combative when at the behavior facility. I returned from lunch through the secured entrance to that unit and found said dementia patient aggressively exit seeking. The resident would not except verbal redirection. When I tried to escort the resident he began to punch me in the face repeatedly. I handled this situation by picking the resident up. I scooped him up like a baby, or how a groom carries his bride. While his room was only 10 feet away, he probably punched me another 30 times (can't count) before I was able to lay him in his bed. I didn't grab him, or strike him, or harm him physically in any way. Its a sad story. I made a snap decision, and I thought that I was protecting him and the other residents. However, today, I met with my administrator and DON, and the administrator talked of lawsuits and J -tags and losing my license. He pulled out a pre typed resignation letter and told me to sign it or I was fired. I signed it. Opinions? Am I fully to blame? Is my administrator out of his mind? I need some clarity.