i was doing a mediocroty run when all of a sudden lefty killed me and my run was over, how did lefty attack me, i didnt buy him or anything

If your risk level is anything above 0 there's a chance one of the four animatronics will spawn

in the run i would click finish as soon as blueprint mode came up

you need to buy the sanitary station, your risk is always set to 3 from the beginning of the game. Sanitary doesnt contribute to faz score so you can still do mediocrity.