The Normandy doesn't mean anything to Hellboy either, aside from any possible historical references in picking the name, but that Garrus is obviously an alien makes it unsurprising that there's a spaceship involved.

"It's nice to meet you both. And I'm... actually from Earth." The bartender brings his drink, and after paying for it and picking it up, he shifty-eyes and elaborates a little. "Well, mostly. More or less. You can probably make some guesses from the name. It's a long story."

Only a very little elaboration, then, as he hates using the d-word or anything directly relating to Hell in reference to himself.