Rex wasn't really worried about zombies and he was under the impression that this was the same case for Cassie- he wasn't sure why though. Sure she kept an eye out for them but they clearly weren't the main priority on her list. His understanding was that the humans that were immune were only such to the airborne portion of the virus. So she really should be a [i]little[/i] more concerned. 'Aliens' weren't their only problem here. Then again the roadway was by all means deserted. It was just them, this abandoned car and a brisk wind.He regarded her actions from the corner of her eye, curious about her intention. Could such a hunk of metal be started up by fiddling under the dashboard? Hotwiring was not something he even recalled hearing about- forget knowing how it was done. 

A slight crackle of branches brought his attention back to the forest and he turned his head to look. After a moment he was pretty confident that it was just a wild animal though and so abandoned the thought of it to get in the car, closing the door and looking at Cassie "that's a good idea. Let's get on it." He unfolded the map to look it over "we have one of two choices, take the interstate and risk getting run down by the aliens or get off at the next exit and take the city streets and risk getting mauled by zombies."