I second Sift&twotimingpete, Both blocks probably fire right. Change the second block to a clean otherwise. (That is if your FacingRight actor value keeps true track of direction.)
Hold up. You are on the right track, but it is an "always" event. Since it is an "always" event, if it is a clean otherwise, whenever the fire button is
not pressed it will fire to the left.
I would change the whole event to a "when key is pressed" event. Then you would only have to check facing and a clean "otherwise" would work just fine.