Crash when you can get rescued easily
From an airport worker and PPL point of view, if I had a long runway with a long parallel grass area, I would chose the runway for a very simple reason: firemen will have access there easily.
By any emergency the position themselves along the runway, and follow the plane, entering runway using the taxiways.
I don't know how good would the firetrucks be in an unprepared grass area, particularly if wet and muddy.