Simply not feeling you must deal with the situation right now.
In the UK for example, the normal beat police do not have guns. If they approach a situation where they feel in danger, they're trained to back off and call for either more backup or an armed response. Turns out most of the time whatever the issue is will still be there when backup arrives. On the other hand, if it's a simple issue, they can just deal with it and there's a much smaller chance someone gets shot.
In the UK for example, the normal beat police do not have guns. If they approach a situation where they feel in danger, they're trained to back off and call for either more backup or an armed response. Turns out most of the time whatever the issue is will still be there when backup arrives. On the other hand, if it's a simple issue, they can just deal with it and there's a much smaller chance someone gets shot.