Two things:
I like new players, even at events like store championships. It means the community is growing, and it's an opportunity to show we're better kind of gamers. It also allows me to refresh my understanding of the rules by teaching those willing to be. Be the bigger person and be patient.
Belligerent people are not easy to tolerate, but you should be taking a lesson from Roadhouse: Be Nice. Ultimately escalating against someone who is getting irrational does not help. Your TO should be involved, especially if he KNOWS that person is new.
No no no. The lesson from Roadhouse is "Be nice; until it's time not to be nice." Clearly, you should have been patient until he started throwing miniatures. At which point you should have flying drop kicked him over the table.
While scratching your sack