"Baseball is a test of character, how you react under pressure".

You never know how you'll react under those circumstances, so maybe we all should show him some understanding.

And I thought, who knows how anybody would react under that.

"I didn't know how she'd react under pressure," he said.

"I know how to react under these conditions," she said.

I don't know how else I could have reacted under the circumstances.

"How do you think Michael would react under these circumstances?"

This will probably be to see if you can think on your feet and react well under stress.

How an excellent security team reacted under stress during an actual attack.

These models allow for prediction of how systems will react under different environments.