For the most part, Steve's interactions with Garrus have shown him to be a composed guy — a little long-suffering about how the people in Abraxas view him but also used to it by this point. They've joked around with each other, they've worked together, and while they may not know each other well, Steve can say with certainty that he's never seen Garrus act quite like this.

Fumbling, nervous. Embarrassed?

Steve tilts his head, not quite gathering why it's such a big deal.

"All right. I was looking for people who might need help getting to shelter." Since he realizes it's odd for him to be all the way out here, too. He draws closer, mainly so that they don't have to keep shouting quite so loudly to hear each other.

"Are storms like this common where you're from?" It might explain whatever Garrus was just doing. It's not that important, probably, but Steve can't help but be a little curious, especially with the turian's uncharacteristic behavior.