Obviously you are requesting he get naked because it's the only way subsonic stuff would hurt... They just bounce off thick denim of course!Get naked, run around a field and let me shoot 300 subs at you then.
To @Crews point though... Yes subsonic rounds don't don't make that massive temporary cavity that the fast movers make.... BUT (big but) if you can kill it with an arrow or a knife... you can kill it with subsonic rounds... They will kill stuff please don't be fooled, but yes you will not cause that immediate velocity damage and things may run off to die while leaking. This is why I do believe we should find stuff that will expand at subsonic speeds so we poke slightly bigger holes