Half life 2

[Jaytee]

Hi All,
I am having a problem finishing the game as I run out of time before shooting the revolving portal plates. One of the things I tried, without success was to reduce the graphics.
Does any one know if there is a trick to this or when does the time begin to count down and what is the period allocated for this task?
Maybe I need to work quicker at an earlier stage of the ascent.

[Jaytee]

Any ideas anyone????