HOW TO DE-ACTIVATE THE BOMB

 

 
1) The 3 switches are identified as left, middle and right
2) Start the timer by turning the middle switch to 3 (1 in the graphic)
3) Turn the left switch to 2 BEFORE the timer runs out (2 in the graphic)
4) Wait for the timer to run out
5) Turn the left switch to 3 so that the box opens and you can take the key (3 in the graphic)
6) Finally turn the right switch to 3 (4 in the graphic)