When a doctor cuts, the medical term is perforates, your colon or other body part, don't expect an immediate admission of liability. Some doctors would rather quit practicing medicine than simply say, "I'm so sorry. This was a terrible mistake." Instead, the common reaction is a litany of excuses to avoid potential liability. Take, for example, this account by the loved one of a cut/perforated colon victim who suffered their injury during a routine colon exam:
"During a colon exam my wife's colon was cut by the instrument the doctor was using. This required emergency surgery and a five day hospital stay. Her doctor said she was injured because she moved suddenly during the colon exam implying that it was her fault. I thought the anesthesiologist was suppose to put a person far enough under that that would not feel the pain and respond by flinching. How can a person be responsible for their actions when they are under anesthetics? A different doctor performed the emergency surgery while her doctor left town for four days.
My wife never had a choice in the matter because she went in for the colon exam and woke up in the surgery room with several holes in her bruised and painful abdomen. The doctor had contacted my wife's daughter for permission to operate because she was still knocked out by the colon exams anesthesia. My wife had to endure this trauma and shock while be fed by IV only for three days."
Unfortunately, this story is quite common. Doctors will try to say it was your fault (like you suddenly moved) which wound up leading to them cutting your vital organ and seriously injuring you. This can be a rather weak excuse, especially if you were placed under anesthetics and should not even be able to feel what is going on during the procedure.
Another common excuse used by some doctors is that the risk of a cut/perforated colon was a "medically acceptable risk" given the procedure. This is a risk for which "the benefits rank larger than the potential hazards." Once again, the legitimacy of this excuse depends on the circumstances of your situation. If it is a routine medical procedure, saying you should have anticipated having your colon cut would probably not be a valid excuse.