Please don't read the tittle and read the Phrase 2 times with natural speed before read the situation about it. ^^ Thank you very much.
"Draw in a deep breath."
Situation :
You're visiting the doctor for a checkup. The doctor wants to check your lungs. He asks you to breathe in so he can listen with a stethoscope.
”draw in a deep breath"
This is rather strange to me, where I am from it is more natural to say:
"Take a deep breath"