This should go to show that even though the pillow did a half-decent job of encapsulating the pop of rapid gas expansion at the muzzle of the gun, which did effectively curb some of the noise, it was still not quiet at all — not unlike an actual suppressor.
Reliable expansion of a heavily-researched premium hollowpoint through a pillow, though … this is my surprised face. Especially Critical Defense, which has the polymer tip. Those have proven to expand reliably even after passing through steel and glass barriers.
I am looking forward to more gun mythbusting with Jerry Miculek. What would you like to see next?