When my pup was 9/10 weeks old he got introduced to our club and all the club dogs (didn't actually meet the dogs, just was in the same area). During practice the dogs are all crated, some in the garage, some in cars. First time my pup went into the garage there were 7 or 8, large, Rottweilers in crates. They started barking (very loudly in an echoey garage) when I opened the door. He startled at first, but after a few seconds ventured in, the dogs were told to knock it off, complied, and that was that....soon he was playing tug and taking treats in the middle of the garage while every now and again a dog or two would start barking, didn't phase him after the initial "what the heck was that?"
After that first startle, he didn't react at all, he'd never been in the garage before, never been on the property before....but he prances into that garage every time afterwords, dogs lighting up or not. I think it's great to expose them to controlled chaos. Of course, it depends on the pup, sounds like yours was a little overwhelmed. I guess I'm saying, I would rather train in a somewhat loud/distracting environment from the get go then a sterile one, unless it's what the dog requires. If you're freaking out, the pups freaking out, and it's just a mess, then don't do it.
"An excess of size is an unserviceable feature for breeding, his powers of endurance, his speed and the smartness of his movements suffer in all circumstances. Giants are never nimble."-Creator of GSD