Like they couldn’t hear the stampede with their own less-that-Trailian senses?  And besides, it looks like they are in the middle of a dance- sort of the John Travolta/ Uma Thurman kind from  Pulp Fiction…  And we’ve probably never seen Mark running from a full-behind perspective…  oh, the vistas we have uncovered since Allen took the pen…

Take cover?  Well I guess there IS that giant tree trunk they could hide behind…