Obstruction, or let them play?

[EsqUmp]

Originally Posted by jmkupka

Never saw a runner just "standing" in a baseline, after having been put out by 20' at 2B.
BUT, said runner, running in that direct path from 1B to 2B, getting hit by the thrown ball after being put out at 2B (by any distance), won't be called for INT by me unless she performs an act of INT (i.e. steps into the thrown ball after running wide of the line between 1B & 2B, or falls down then stands up into the throw)

Okay. So rather than "standing" let's say she continues to "run." Why is running not an "act" but "laying" on the ground after just missing a ball is not an "act?" Are they both not continuing to do what they were legally permitted to do a moment earlier?