City says it shouldn't pay for officer's fatal wreck

The arguments for or against here are immaterial, because the law clearly states that if on the way to or from work in a work provided vehicle, then legally you are on duty. All arguments should be aimed at the legislature.

You are comparing apples to oranges. HAD he stopped to assist, of course he would have been "on duty" - although point in fact, if he was on duty, he was entitled to be paid for his time. But he didn't stop, he was speeding because he was late to work. If any other citizen had done that, he would have faced prosecution for reckless homicide, at the least.