Dropped third strike question

[chapmaja]

OK, had this one today. Coach wasn't happy with my ruling. Was I correct or not? Fed rules.

2 out, none on base. Uncaught 3rd strike on B3. B3 starts walking toward the first base dugout (enterence is about even with 1st base). She never enteres dead ball terriroty. The catcher rolls the ball to the pitching circle as the defense heads towards their dugout. I called the third stirke, and went in line with first base and watched for somthing else to happen (either she entered DBT or the defense makes a play). Finally, B3 realizes the situation and goes to first base. By the time she arrives at first base, the defense has huddled in live ball territory outside the dugout. I call B3 safe, which does not make the coach happy. She starts coming over to argue as B3 starts going from first to second, then on to third base. The DC realizes this and the players run onto the field, grab the ball and almost get B3 at third.

The closest thing I can find to this is the casebook play on page 50 Situation 8-1-1. There are three instances where B3 could be called out on a D3K situation. First, she enters DBT, which did not happen. Second, she does not reach first base by the next pitch (again not applicable). third, the infields have all left the diamond before she B3 reachers third base. This is the one I am questioning. I can not find anywhere in the rulebook a specification for leaving the diamond. Does this mean leaving live ball terrritory (in which case the call was incorrect and she should have been out), or does it mean leaving the dirt area of the diamond.

P.S. Due to several injured umpires, I was working a JV game 1 man today.