Right. This is because you don't have the final variable change.
First thing first, change your variable back to true, as the instructions dictate.
Second, In section 3, it instructed you to change the slaying variable to false IN THE BODY OF THE LOOP.
So per the instructions on section 3, your code should look like this when you go into section 4:
var youHit=Math.floor(Math.random() * 2);
var damageThisRound= Math.floor(Math.random()*5 + 1);
Notice that within the while statement, it changes the slaying variable to false? This is so when you do add the if statement, it will prevent it from going into an endless loop.
At this point, you should be able to just follow the instructions in section 4 to add the if loops.