Okay, really thinking back now, I think I know what's going on. When I picked up my car from service (timing belt job, including cam shaft/crank shaft seal replacements, etc.), that's when my factory BOV's vacuum nipple was broke. They attempted to JB weld it but it didn't hold up well. When I was picking up my car from service, they brought it to me and parked it in a spot.

I popped the hood to inspect the work (making hte sure a/c, alternator, P/S belts were replaced, etc.) This is when I noticed that they left a torque wrench laying on my valve cover and that my factory BOV's nipple was broke. I got one of the tech managers to come out. He came out with the tech that was working on my car and basically said "well, that's a good thing that you caught that, that would of been a real expensive tool to lose". I brought up the broken BOV to him and he simply told his tech to apply more JB Weld/RTV to "rig it back together". I brought this up to the service advisor and he basically said "oh sorry, the tech was of hit it when he was working on your car, those things break easy, being that they are plastic". He offered to replace it, if I payed for it. I wasn't in the mood for arguing (especially since the factory Bosch BOV is a POS and they wanted a rediculous price for replacement). I basically told him not to bother. Looking back, I should of had them at least document it though.

Anyways, what I think may of happened, was perhaps the tech unhooked the factory BOV or I/C to inspect it, when he broke my valve, and perhaps dropped the bolt in there without realizing it. Now, the bolt may of sort of wedged itself down where the factory upper I/C pipe sort of kinks.

Driving the car home, was basically in stop and go traffic, so I wasn't boosting high at all. Now, when I went to go to work later on, I did get on the gas a little bit more, and that's when my car all of a sudden started accelerating on it's own and pegged at redline. So, something was holding the throttle body plate open. I had the car flat bedded in immediately. This is when the techs were not able to "replicate the symptoms I described". I know for a fact that something was wedging that thing open though. But, I guess it could be possible that during the process of having it towed to the dealership, the bolt may have slipped through the throttle body plate, fell down one of the intake runners, and has been sitting in the valve chambers since.

Now, at this current time, the bolt may have finally managed to wedge itself between the exhaust valve. I suppose it could be possible that the bolt was rattling around in the valve chambers right?

As you said, those valves open and close quickly, so it would make it rather hard for the bolt to roll around and wedge itself in between a valve at the right moment.

Do you think that this could be possible?

What's even funnier, is that my service advisor told me that it was a 10mm bolt.

3 days later, he called back, saying they were not going to cover my repairs and that the bolt they found, is not an official "Mitsubishi bolt". Sounds to me like they are try to cover something up. Quite frankly, this whole thing really wreaks of bull shit.