I don't believe the ball becaomes automatically dead. Her's the partial rule I found: "Type B obstruction occurs when the obstructed runner is not being played upon. The ball does not become dead; rather, the umpire calls "That's obstruction!", but play is allowed to continue. While play continues, the umpire privately decides what base the obstructed runner would have reached without the obstruction. The obstructed runner is now "protected" until he reaches that base. When playing action stops, the ball will become dead and the runner will be awarded that base if he has not reached it. If he was put out before he reaches that base, that out will be nullified and he will be awarded that base. If the runner reaches that base safely, the obstruction is ignored. If the runner continues past that base, he does so at his own risk, without protection. There is no minimum base award for type B obstruction."