Tony wasn't shot and killed... it's a heart attack during that last onion ring. Notice how his last line references the onion rings he ordered. Notice how his family members are making good progress chewing through theirs? Notice how when the door dings Tony happens to stop chewing and makes a weird face for a half second? Do you pause masticating your delicious onion ring just because you see your daughter entering through a doorway as expected? I think not.
The other shots of him stressing about who is coming through the door are there to establish that there is extra undue strain on his heart caused by all the worrying. The stuff about never hearing the bullet that kills you is a red herring. By Tony knowing that, and expecting that, it can't be the manner of his death. It is in fact contributing to his malaise worrying if "Members Only Guy" is there to kill him. He never sees his bullet coming because he is too busy expecting a literal bullet. Tony's bullet is the final onion ring.
The other shots of him stressing about who is coming through the door are there to establish that there is extra undue strain on his heart caused by all the worrying. The stuff about never hearing the bullet that kills you is a red herring. By Tony knowing that, and expecting that, it can't be the manner of his death. It is in fact contributing to his malaise worrying if "Members Only Guy" is there to kill him. He never sees his bullet coming because he is too busy expecting a literal bullet. Tony's bullet is the final onion ring.