Garrus is odd because he's definitely very squishy, which I wasn't expecting. He's less tech-orientated than Tali, so she ends up having more shields than Garrus. He's pretty much a glass cannon, really.
Yeah, that section is very difficult. It's probably the worst for an infiltrator, as you can't really use sniper rifles against a moving target. The key with that section is to find the right cover and just hug it at all times until a hopper stops hopping for a while. It's easier to do if you've levelled a tad (as in, not go straight to Therum).Hoo boy, am I ever glad I saved before I got to this cut-scene at the top of a hill. I'm not joking, it took me about 15 attempts at this bit with all of us getting jumped by a load of enemies and one-shot killed by these really smurfing annoying jumpy skinny-frog things. I finally figured out that I was hiding behind the wrong crate which gave them too many angles on us. I ran behind a different crate to the left and it shielded as all pretty well. Managed to take everything out finally with all my team still alive (just!)