So I'm at the part of killzone where I'm going into tunnels in the orbis station (Like the second or third stage) and I find it's REALLY hard to pass. The guy's take like three rounds to kill and they keep coming.

I was wandering if anyone could give me tips on how to kill faster, if you know what part I'm at tell me some tips for that ect.

I haven't played it myself (not a fan/very good at shooters >.>) But these might help you;
http://www.gamefaqs.com/console/ps2/game/918762.html
Game FAQs is love <3 lol

Aim at the face. That always works. Keep covered use grenades to flush them out from there hidey holes, and then open up on them when they come out.