I would agree that sticking around when you are nearly involved is a good thing. If anything, for your own protection. Who knows what sort of story "the other guy" might make up about your driving which he might claim was a contributing factor in his collision. Although comming over a median would probably not lend itself to such a story ;p
In Oregon, there is actually a legal requirement to remain on the scene of a situation like this. If you leave, you could be cited for failure to perform the duty of witness to an accident.
(ORS 811.117) Although i've never heard of someone ever being cited for this, except in a few oddball collisions where there were other factors involved.