As the doctor in the Normandy, you were obligated to heal everyone. Since Jack was one of the best soldiers aboard and with a lust for blood, she'd go out every time possible, which only meant healing her a numerous ammount of times, and she didn't like that.

Scratches, shovings, punches.

Heck, you couldn't even get an IV on her.

"I said don't touch me!" She shouted, shoving you to the wall.