Strange. In that case does being inside the event horizon isolate a given piece of matter (prior to becoming part of the singularity) from outside gravitational influences, no matter how strong... even another black hole? Is this because of the propagation speed of gravity?

Your question got me thinking: nothing can escape from inside the event horizon, but what if we suddenly deform the event horizon so that something slightly inside is no longer inside it? If you have a second black hole moving at relativistic speed tangent to the event horizon (or two black holes orbiting each other very rapidly) could the event horizon be deformed so that a signaling device that was slightly inside the EH send out a pulse of very redshifted light?

I mean if this was true then the laws of physics would also have to be constantly changing so that shrinking objects would behave in the same way at every scale, instead of having all kinds of changes related to surface to volume ratio, differences in behavior of forces at different scales/distances etc. And if you need the laws of physics to change constantly to explain a theory, and the theory is only provable/observable from outside our universe, it doesn't have any usefulness to us, other than as an intellectual curiosity...