[soundedlikeastrike]

Sit.
R3, R2, 2 outs.
Ground ball to F5, R3 and R2 are going on contact.
F5 gloves the ball, runs at and tags the hung out R2 for the 3RD out.
R3 touches HP prior to the "tag" of R2.

BR is 1/2 way to 1B "when the tag of R2 is made", BR kicks the dirt and heads towards his 3B dugout to fetch his glove and hat.

F5 seeing BR stop, now throws to F3.
F3 steps on 1B and appeals; "the BR did not advance and touch 1B".
The advantageous 4th out is: "recognized by the umpires, as the 3RD out, on the BR, before he reached 1B, wipe off the run.