Thread Subject: Simulink iteration blocks: how they work?!

Maybe I didnt understand how simulink iteration blocks like While or For works.
I have a For iteration and inside it 2 while iterator; these subsystems have IC so that if the sensor value is below a costant while#1 should run, as the sensor value is higher while#2 should run. Now the problem is that both whiles are runned at the same time....I can say this because there is a command that is present in the while#2 only cycle and it run even if the IC if false!
I though that once the model enter a while cycle it runs the blocks inside the while subsystem until the IC is true; when the IC become FALSE it exit the cycle and move on to the next step. Why its not working like this? :(

Anybody can help? Still havent solved the problem :(