Well, that was part of the selection process! I recall one anecdote (possibly from the book "The Right Stuff") where they were testing one candidate (possibly John Glen) and he was strapped into the multi-axis spinning chair, carrying out tasks with smoke and flashing bright lights going on, when they dropped a ton of scrap metal onto a big metal plate right behind him. Apparently the only evidence that he'd even noticed was a single big jump on the heart monitor, then back to normal. Some later evidence that "the right stuff" didn't always work well when forming a larger crew but no doubt that at the start of the space programme, "calm under pressure" where "pressure = imminent death" was an absolute necessity...