Note the paper's definition of medical error:
"Medical error has been defined as an unintended act (either of omission or commission) or one that does not achieve its intended outcome,3 the failure of a planned action to be completed as intended (an error of execution), the use of a wrong plan to achieve an aim (an error of planning),4 or a deviation from the process of care that may or may not cause harm to the patient."
That's quite broad