NCAA Safety Question

[ljudge]

Play:

3rd and goal on B4. Back A32 takes a handoff from A11 at the B-5 and runs to the B-1 where he fumbles the ball into the end zone. B33 bats the ball in the end zone and the ball hits the end line pylon.

The ruling I was given is:

Safety, 2 pt for B. 4-2-3-b, 8-5-1-b, 8-5-2, 9-4-1-c

I'm misunderstanding (I believe 8-5-1-b). I had this being A's ball 3rd and goal from the 1/2 yard line. I thought A would be responsible for the impetus of the ball and since B33's foul is illegal (happened in the endzone) the penalty would be marked off from the end of A11's run, which is the 1.

Can anyone explain this so I get it thru my thick head?