BOSTON—Rolling down his window to circulate fresh air through the interior of the emergency vehicle, ambulance driver John Hendricks became visibly enraged Wednesday when a patient he was transporting vomited without warning. “You have to be kidding me, dude, you can’t do that in here,” said Hendricks, sliding the collar of his shirt over his nose while recounting how he had just finished cleaning up after three other passengers that same day. “I knew this one was going to be trouble—pale, disoriented, extensive head trauma, that’s the puking type. I should’ve just left him there. It’s, like, have some respect, I’m trying to make a living, man. How would you like it if I came to your office with seeping cranial wounds and, like, barfed on your desk?” At press time, Hendricks was threatening to pull his ambulance over until his semiconscious passenger agreed to stop bleeding on everything.