Third Strike "Legally Caught"

[mbyron]

Sorry dude, you blew that one.

Originally Posted by Rule 8-3-3

Each runner is awarded...

(f) one base beyond the last legally acquired base, if in the umpire’s judgment
the runner was attempting to advance at the time the ball becomes lodged
in an offensive player’s uniform or equipment. If the lodged ball occurs during
play when the batter-runner was attempting to reach first base, the batter-
runner will be awarded first base. Preceding runners will be awarded
bases needed to complete the award.

Also, the BR's leaving the field during a dead ball (as you're walking toward PU) would not constitute an out.

In your play, this is a foul ball. Runners stay put unless they were stealing on the pitch, in which case they advance one base.

Edited to add: you can't rule this a catch, because F2 did not securely possess the ball in his hand or mitt.