You can’t blame Chi Tahani for puking on Paula Abdul. Last night, after the young So You Think You Can Dance contestant twirled her little heart out to Beyoncé’s “Countdown,” she received a round of hugs from the judges — only to vomit all over Abdul. While Tahani chalked up her nausea to Paula’s embrace — “She just squeezed me too tight!” — nerves might have played a part. And who wouldn’t be anxious after landing a string of somersaults in front of nearly five million viewers, then hugging a pop legend on national TV?

By puking, Tahani was only doing what evolution trained us to do. Biologists consider anxiety a psychological, physiological, and behavioral state that’s triggered by threats to wellbeing or survival — in young Tahani’s case, the presence of Paula Abdul’s outstretched arms and a massive audience to boot — which comes with its share of unfortunate side effects.

The anxious state is, essentially, a state of preparation: The body’s systems kick into overdrive, getting ready to deal with or escape from a potentially dangerous situation (early humans had significantly more threatening things to deal with than aging pop stars). Our senses become aroused, we amp up our expectations, and our autonomic system prepares for battle by speeding up the heart rate and forcing blood pressure to rise. What Tahani experienced on stage was a modern-day, Fox TV equivalent of coming face-to-face with a prehistoric predator, giving her body no choice but to enter the fight-or-flight response.

Some brains, like Tahani’s, occasionally go overboard when getting ready for battle, perhaps because they overestimate the danger actually posed by the threat. An unfortunate side effect of over preparation is nausea, which, in this case, causes one to projectile vomit all over a pop star’s jacket. The physical exertion of the dance itself probably played a role, too, by churning up Tahani’s half digested pre-performance snack.

People with anxiety disorders — about 3.3 million Americans — exist in the over prepared state all the time. That’s not to say they are always on the verge of puking — but they do have to deal with the constant presence of anxiety’s other side effects, like restlessness, insomnia, and excessive worrying.

Luckily for Tahani, her anxious episode passed as quickly as it came up, and she was able to brush off her body’s response like a champ, saying, “all the happiness came out on her jacket” after Abdul squeezed it out of her. Her performance — from start to retching finish — was, in a word, sick.