When an attact starts,protectees are almost always safer when they are being moved from where they started to a different spot.This could be short or long distance.
Reasons to move:
-Attackers lose accuracy.
-Other hazards may be present (unknown at that instant).
-Gives protectors time to re-group and interpert what happened.
-Injuries may not be obvious in that instant (Example :Reagan attack).
-Easier to assess the impact outside of public view.