..The tunnels confused the crap out of me - I wasn't sure if my vision was closing in and I was about to pass out, or if it was just the light (there were lights and generators for the race, but even then it was dark).
Been there... Freaks the hell out of you.. Plus you don't know how fast you're going
Been there... Freaks the hell out of you.. Plus you don't know how fast you're going