I'm not sure where they got the notion that emergency services are the only other field where people go on-call. Plenty of industries operate 24/7. I worked in

I'm not sure where they got the notion that emergency services are the only other field where people go on-call. Plenty of industries operate 24/7. I worked in high volume manufacturing where process engineers could be on-call 24/7-365 unless you explicitly asked a backup to cover you during a vacation or weekend. Depending on the part of the process you owned, that might mean a middle-of-the-night call a couple times a month or several times a week. No human lives on the line, just lots of money.