It should be working. It's hard to guess the problem without seeing actual code or a file. But, "if", "while", etc should work.
Also, depending on the event, like, for instance, if it's something that you need players to see every step (like an energy bar incresing), you should use a timed loop (every X seconds) or a timer event, and add the condition to stop it at the beginning.
Hope this helps...