They didn't stay away for long - and are too far away to charge at. Time to get creative.
What do I need to do?
Have a good look around the room - you're looking for something that can hit the turrets without putting you in the firing line.
Hmm...
The pellet dispenser in this room is constantly rotating, but always fires at a portal-friendly surface (the exact locations are the cracked panels!)
How does that help me?
Energy pellets are quite powerful. Maybe you could use them to destroy the turrets?
Have another look at the walls to get an idea of where to aim.
Help me out.
Some of the turrets are easy to deal with - just put a portal on the wall next to them - but for others, you'll need to look for their aiming lasers on the walls. If you create a portal on the panels where the laser is resting, the pellet will usually hit the turret.
Repeat the process for every other turret, and when they're all deactivated, you can turn your attention to the moving platform.
Guide help
This is the low-spoiler guide for "Dealing with the turrets" puzzle in Portal. Unlike in normal walkthrough, you get gradual hints on how to solve the puzzle. Click the big button below to see your first hint. If the hint contains a spoiler, you will be warned about it before clicking.
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