Interference?

[playball13]

FED Rules, Bases Loaded, 0 Out
hard hit ground ball, F3 takes a step to right ball goes by and hits R3 on heal. PU rules safe no interference. Not sure if he thought F3 deflected the ball. DC asks for help with BU who apparently rules F4 had a possible play on the ball R1 is ruled out, runners return and BR goes to 1B.
If the ball goes past an infielder and hits a runner is runner out by interference?
If F4 was playing up the middle or doesn't make much of an effort for the ball is it still interference?

[UmpSteve]

Once a batted ball passes an infielder, runners aren't out if hit by the batted ball unless an umpire judges another fielder still had a play (opportunity to make an out) on the ball. Since either umpire can call interference, whichever one believes that to be the case can call the interference.

To your secondary question, no, if no opportunity to make a play, then live ball, sorry it hit the runner, but no interference, play on.