The point of this question is to find out whether you can balance company policy with common sense. So a good answer might go something like this, “Well, one of the first things I’d do is familiarize myself with your procedures ahead of time so I could make sure my response is in alignment. Barring that, I’d find out what type of first response was needed – both to treat the injured and resolve the situation if it was ongoing – and get that response started.”