Better to use the jump to x action part for time sensitive loops as there is no method for delaying loops with Lua script, well not in VS anyway.
What Machtnix just said is more or less correct.
1. create a called by other action block.
2. create a value & name it something like "loop_amt".
3. inside of the called by other action you created add some actions along the lines of these...
if value 'loop_amt' is greater than 0
execute a script > (add the line for fading to scene brightness to black)
pause for x time (whatever delay value you set in script above)
execute a script > (line for restoring scene brightness)
pause for x time (whatever delay value you set in script above)
jump to action part #14. just call the called by other action block whenever you want to trigger the blink. make sure you set the "loop_amt" value before calling it though, that way you can specify the amount of times it should loop.
P.S: remember what I mentioned earlier about using math.random() / random values for creating more dynamic approaches to things. You could create random delay values, random brightness values, random loop amounts, etc. All sorts of things can be done by generating random values.