blue canary
n.— «Col. Rich Greenwood, UHP deputy director, said the troopers who arrive at an accident first are usually the ones in the most danger. He said the program will prevent those first-responding officers from becoming victims. “Officers will no longer be a blue canary.”» —“Software shields UDOT from hazards” by Pat Reavy Deseret News (Salt Lake City, Utah) Oct. 5, 2000. (source: Double-Tongued Dictionary)
Further reading
Understanding the varieties of conversational styles can mean the difference between feeling you’re understood and being insulted. “High-involvement” speakers interrupt or talk along with someone else to signal their enthusiasm...
When you’re distracted by trying to get the perfect photo at a wedding or fiddling with your camera during a solar eclipse, you’re missing out on some of the experience itself. There’s a term for this: It’s called...