Event occurs, the example does not expect and does not intend, in time and in one place. Occurs without what tell in advance, but there is a cause-and-affect. When it occurs, and then causing injury or death of a human being.
The incident did not expect and do not intend on time and in one place. Occur without advance but there are indications cause and effect. When this happens, it causes the injury or death of a human being.
The incident was not expected and not in place of one. Happen without a prognostication but causes and impact. When that happens, then cause injury or death of human beings.