Minemrys:

and why is it that they kn0w it all of a sudden when the plot requires it?

Some but not all
but you know it's just a movie for entertainment

# one kick can kill enemies(when they are many) but actor will receive ten bullets and still fight back
#Nigerian movie.. Man gets shot in the head but his leg is bandaged.
#Hollywood...a kiss can revive a dead man *** SMH # you can receive 100 punches on your face and never lose a tooth.
#You will always marry your Crush**dont even wait**.. #experience.
# A broken leg can be fixed instanly.
# Any disaster gives you Superpowers: electric shock,acid bath,insect bite, chemical disintegration,
# you can fight 50 men and never get hit by one
# A girl will fall for you once you sing for her
... I'm still thinking