Question on a case play:

[Tru_in_Blu]

I had a conversation with a fellow umpire today. We were discussing when run(s) score or don't score when and how the third out of an inning occurs.

While doing some research on the matter, I came across an old case book play that I had from 2009.

It reads:

PLAY 5.5-3

(FP Only) With two outs, R1 on 3B, R2 on 2B, B5 strikes out, but the ball gets by F2. R1 scores and R2 is out at the plate. B3 failed to run to 1B and F2, after tagging R2, throws to 1B for the fourth out. Does the runner score?

R1's run is not nullified. A "fourth out" appeal to nullify a run must be on the runner who has scored. (5-5C)

I'm interested in hearing some thoughts on this play.

Thanx.