At 1/8000th of a second, captured only 30 times a second leaves a lot of time for a moving 2000 foot per second projectile to not be in frame.
“Mist” from the President’s nicked ear, however, might float in the bullet’s vacuum trail for an instant.
Now I want to know if it really WAS set at 1/8000th.
If the photo was really taken at 1/8000th of a second shutter speed, then the streak in the image had to include “mist”, as you mentioned, or the bullet’s shock wave vapors. A short (one inch or so) bullet traveling 2000 fps would leave only a 4” streak at that shutter speed.