Stuck in HL2 episode 1...at the core. Help!

How do I get to the balcony overlooking the four rotating blades?

> I've reached towards the top of the core where there is a balcony
> overlooking the 4 fan blades (above the pulsating bubble).
> I can jump up on them with nowhere to go really.
>

I have gone past the corridor where there is an exit with the shooting
plasma balls. I am where there is a pulsating huge ball, I think it's
the core of the reactor. There are four bridges. How do I go past this
level?

> try squeezing into the corridor using a crouch
> jump and dodge the plasma balls to get to another exit?

Thanks for your assistance.