During my time as a police officer, I was privileged to spend my last 12yrs of service as an observer with a major UK metropolitan force. During that time I have lost count of the number of jobs, pursuits or whatever I went on in marginal but legal weather conditions to fulfill our role. What was always comforting to know was, one, I felt safe in the hands of a competent pilot with a lot of experience behind him and, two, we had two engines.
Believe me if you are engaged in a pursuit over a major city during the night and you get a chip light or a fire warning in an engine as I have experienced, it's nice to know you can lose that engine if necessary and still FLY.
Would I like to have experienced that in a single or be prepared to do so? No Thanks and I don't think I am alone.