Fighting urges.

The two of you barely make it half a block before you see motion along a nearby rooftop.

When you look that way, you see an Infected crawling across the rooftop, naked in the moon lite, it's attention obviously on the pair of you.

It shifts it's position, stroking it's cock rapidly. it's hips thrust involuntarily, it's eyes locked on the two of you.

Run!
Hit the deck.
or
Put yourself between Brittany and the Infected.