The way I see it...
It wouldn't matter what poundage the air rifle had, if a pellet was fired through a damaged or poorly aligned silencer, there would be enough momentum to damage the pellet or to fragment it, and get the pieces to the end of the silencers muzzle and exit it...
What interests me after this point, is what minimum velocity would be required for those pieces of pellet to penetrate the surface of the skin and end up is Sheila's neck as shown by Xray?
Would there be sufficient poundage or velocity to carry those fragmented pieces of pellet into Sheila's neck, once it had passed beyond the muzzle of the silencer, and gone into exit mode before entering the neck?