I just tried live view without setting "D4" enabled and self-timer enabled;
After pressing the shutter release;
1) Self-timer runs/completes
2) Shutter closes
3) shutter immediately fires for the shot
4) shutter opens again
Since nothing is seen through the viewfinder during any of the above, presumably the mirror stays up at all times.
I was using this last night with a D800 for 8 second exposures with a 200mm lens on a less than optimal tripod and it worked rather well.