Runners at 2nd and 1st. The pitcher must have really been rattled to try a pick off move to first and have the ball end up in center field. In the major leagues it is a legal advance. According to the rule book, in cases where a pitcher balks and throws wild, either to a base or to home plate, a runner or runners may advance beyond the base to which he is entitled at his own risk. Easy call, Dead ball as soon as the balk occured.
All runners advance one base.
That is assuming, 1. Pitcher was on the mound at the time of throw and was not that of a fielder. In that case, dead ball, charge strike to batter.