Ok, more info for you (it's clear in
my head, why can't
you understand it?
)
The slide and the catch were both clean - my judgement is there was no OBS on this portion of the play. F2 was not blocking the plate without the ball prior to the runner's slide. F2 caught the ball, and applied the collapsing tag as the runner was sliding in, effectively stopping the runner's motion to the plate, and preventing the runner from even reaching HP.
As they tangle, motion towards the plate is stopped. F2 loses possession, reaches for the ball, and applies the tag a second time. The runner could not move because of F2 on top of her (and consequently probably did not know that the ball had come loose, so she didn't make any further attempt to get to HP.