What's even funnier is that Meredith pointed out the exact same thing on the Pilot episode during their first day as interns.
DR. BAILEY: I have 5 rules. Memorize them. Rule number 1. Don’t bother sucking up. I already hate you, that’s not gonna change. (points to the desk) Trauma protocol. Phone lists. Pagers. Nurses will page you.
(They grab their stuff of the desk as Dr. Bailey starts walking away. They rush to follow.)
DR. BAILEY: You answer every page at a run. A run! That’s rule number 2. Your first shift starts now and lasts 48 hours.
[HOUR 1 flashes across the screen]
DR. BAILEY: Your interns, grunts, nobodies, bottom of the surgical food chain. You run labs, write orders, work every second night until you drop and don’t complain.
(She leads to them to the on call room)
DR. BAILEY: On call rooms. Attendings hog them. Sleep when you can, where you can. Which brings me to rule number 3. If I’m sleeping, don’t wake me unless your patient is actually dying. Rule number 4. The dying patient better not be dead when I get there. Not only will you have killed someone, you would have woke me for no good reason. We clear?
(Meredith raises her hand)
DR. BAILEY: Yes?
MEREDITH: You said five rules. That was only … four.
(Dr. Bailey’s pager goes off)
DR. BAILEY: Rule number five. When I move, you move. (She starts running down the hall, yelling at doctors). Get out of my way!
That's also why Cristina was so disappointed when her pager didn't go off right after.