cheeseonastick---
Like your girlfriend, my son, too, has asthma. He had no problem with MF, but he had given himself a quick inhaler treatment earlier in the evening.
If your girlfriend skipped her treatment (and it is possible to do that, especially when you're having fun at CP), that may have contributed to her breath loss.
My son has never had breathing problems at CP, other than weather-related (muggy, high mold count, etc.), although I thought I, a non-asthmatic, was going to pass-out a couple of years ago, from the fumes of the mini-racers at Challenge Park!