Admittedly, as a GM I have yet to run into this problem, at least on a level that wasn't easily manageable. But I have witnessed it as a player. It sounds like Bonk is an individualist style player. They can be frustrating to work with, but if you have an entire party of individualists (prefer to remain in character at all times, oft-chanted mantra of "it's what MY character would do", etc) then things *can* work out better. However it really depends on just how individualist those players are with their characters; I had a rather miserable experience in a game of D&D due in part to this playstyle. These players had no concept of the social contract and would dick each other over in-character. Not only that, but they all had these secrets that they just HAD to keep away from the other players because OOC = cardinal sin to them. SECRETS ARE DUMB AND NO FUN FOR ANYONE.
I know this doesn't directly answer your question, but my opinion is that collectivist players are better to work with. They allow certain redundant actions to be assumed (like sharing party information, i.e. "PC Hive Mind"), which allows you as a GM to get to the meat of the adventure sooner. The more you devote energy and thought to pointless things like keeping secrets from one another, or having to repeat information to other characters the worse off you are. I can't emphasize this 'secrets' thing enough; If your character's secret is really cool, then why wouldn't you share it? If it's not, why have it? It only leads to talking to the GM in the other room for 5 minutes while the rest of the group twiddles their thumbs. This happened multiple times per session in that miserable D&D game I mentioned. I could go on about that game for its other flaws, as it was easily my worst gaming experience, but the talking in the other room thing is one of the problems that can arise from a group of individualist players who don't trust each other to keep OOC information OOC.
Back on topic: My suggestion to you would be to sit down with Bonk and talk to him. Just explain that sometimes, the social contract needs to be observed and some things need to be let go even if they aren't 100% in-character. At the same time, I would ask him why he gets so frustrated so easily. Just cut to the core of it if you can. Compromise is good, but you still have to get Bonk to realize that some degree of meta-gaming is actually good. Good players can use out of game knowledge to make the game better, and constant immersion doesn't automatically make for a good game.
Edit: ^ I agree with Patrick; If Bonk continues to be a problem after talking it through with him, then it might be best to explain that your group's playstyle doesn't mesh well with his and agree to part ways. Bottom line: It sounds like Bonk is being a dick, and he's in the minority.