Yup, it's barbaric to think about. What's eerie is he probably did his research to figure out what angle/location would provide the quickest death. Still, missing the mark and having to deal with that pain while waiting for your lungs to drown in your blood can't be a pleasant way to go.
OT, but 5 years ago I responded to an attempted suicide where a guy put a shotgun under his chin...while he was leaning over to pull the trigger the barrel moved up on him and he ended up blowing his face off, but living. Was quite a sight.