To get your expected result :
Event 5
Shift is down
Bohater animation "Run" is NOT playing => Set animation "Run" to play
Event 6
Else
Shift is NOT down
Animation "Walk" is NOT playing => Set animation "Walk" to play
Note that the first frame of your "Run" animation has a speed of 100, making it stick to that frame for the longest time.
Put it at 10 and you will see your animation working easier.