out?

[gtfreek]

long time no chat...anyway...heres the sitch
asa slow pitch womens, bases loaded batter hits ground ball to short stop, all runners begin to advance due to the forces, as the short stop moves into the base line to tag the runner advancing from 2nd she stops and the moves backwards towards 2nd, my partner behind the plate calls here out and thats the end of the play so far as this sitch goes...coaches want to know why and the explanation given was cuz she was avoiding a tag, like running out of the base line...help me understand plz...I have not interpreted base line and force out sitches like this, except running to first