Not sure where you got the idea that #6 won’t penetrate drywall but that is wrong.
https://www.youtube.com/watch?v=uERIjpiBvog
There would be the intruder between you and the wall. I’m not talking shooting at a blank drywall. The #6 will not go through the guy and into the drywall x2 into the next apartment. Close in, the pattern diameter would be less than 6 inches.