ART. 2 . . . It is a safety when:

a. A runner carries the ball from the field of play to or across his own goal line, and it becomes dead there in his team's possession.

EXCEPTION: When a defensive player intercepts a forward pass, fumble, backward pass by an opponent or catches a scrimmage kick or free kick between his 5-yard line and the goal line, and his original momentum carries him into the end zone where the ball is declared dead in his team's possession or it goes out of bounds in the end zone, the ball belongs to B at the spot where the pass or fumble was intercepted or the kick was caught.


I missed that key "his team's possession."