This is the only way I can imagine this happening.
Team A has scored a touchdown and attempts the extra point. The kick is blocked and recovered by B20 who sprints toward the end zone. A30 runs him down, hits him from behind, and strips the ball, which is recovered by A30 at the A 3 yard line. A30 is chased into his own end zone by B16, where he is tackled. The score is now 6-1.
EDIT: got my teams mixed up. A surrenders a 1 point safety and B has one point on the scoreboard.