LBR when F1 catches line drive?

[IamMatt]

The runner was not physically "still in the process of moving;" she had taken a very short lead off of 1B and was stopped. I was interpreting the LBR to mean that R1 would have had to immediately either return to 1B or attempt to advance to 2B (and be called out due to not tagging up); sounds like you are saying that the act of going back and tagging up at 1B then advancing to 2B is one act that falls under "immediately attempting to advance?"

And if that is the case, then tagging up at 1B would not be considered "stopping at a base for any reason" (I am reading 2002 ASA rules, 8-8-T-2) but part of the act of immediately attempting to advance?

Thanks for helping me learn.