Everybody knows that you're immune to bullets while climbing/descending ladders. Haven't you seen any movies lately? They always ricochet off, barely missing the protag as they flinch in a dramatic fashion.
I recently set up a test with some friends and enemies to see if this Hollywood/Vinewood ladder theory is true. After being on a ladder for over an hour, and having over one thousand rounds shot at me, I can assure you all, it is impossible to be shot when on a ladder. Science, bitches.