A few years ago I listened to a seminar where a few real professional doctors discussed the hospital scenes in movies or TV shows. They mentioned that those dramatic and chaotic operation room scenes where the doctor yells commands with a loud voice look so fake to them. In a real operation room, everyone (including the doctor and the nurses) is highly trained, works in tandem calmly and efficiently -- there's never a need to raise voice.
There's a big difference between the (controlled) chaos of an ER vs scheduled surgery, but it's still dramatized for TV obviously.