My two cents...
My understanding was that whenever there was an interference or obstruction the umpires could signal a delayed dead ball which is the right arm straight out with a closed fist. Once the play was over a decision needs to be made on what would have happened had the play not involved interference or an obstruction. This is all while understanding that if a runner on second runs into the SS while making a play on the ball she is called out immediately. In this scenario, I would say that the batter is out based on the caught ball and even though there was contact at first base between the OP and the DP the contact appears to be made based on the errant throw. Without seeing the actual play I think I would be justified in saying that the runner would have returned safely back to first base because of the errant throw and she should be able to remain on first base with there now being two outs.
Where I think this situation could really get sticky is after the girl returned to first, she tried to go to second because the ball when wherever it went. At that point you could have an obstruction situation where she would be sent back to first base.
It's been a few years but I used to umpire a lot of high school softball and again it tough to understand without seeing the actually play. Based on what I've read though I think this is what should/could have happened. Could be wrong though...
My understanding was that whenever there was an interference or obstruction the umpires could signal a delayed dead ball which is the right arm straight out with a closed fist. Once the play was over a decision needs to be made on what would have happened had the play not involved interference or an obstruction. This is all while understanding that if a runner on second runs into the SS while making a play on the ball she is called out immediately. In this scenario, I would say that the batter is out based on the caught ball and even though there was contact at first base between the OP and the DP the contact appears to be made based on the errant throw. Without seeing the actual play I think I would be justified in saying that the runner would have returned safely back to first base because of the errant throw and she should be able to remain on first base with there now being two outs.
Where I think this situation could really get sticky is after the girl returned to first, she tried to go to second because the ball when wherever it went. At that point you could have an obstruction situation where she would be sent back to first base.
It's been a few years but I used to umpire a lot of high school softball and again it tough to understand without seeing the actually play. Based on what I've read though I think this is what should/could have happened. Could be wrong though...