28 Weeks Later (2007)

During the original outbreak of the Rage Virus, Don, his wife Alice and four other survivors are hiding in a barricaded cottage on the outskirts of London. They hear a terrified boy pounding at their door, whom they let in. A few minutes later they find that the infected have followed the boy to them. The infected attack and kill most of the survivors, while Don, Alice and the boy are chased upstairs. Don is separated from Alice and the boy by the infected and jumps out of a window, leaving them. Don, closely pursued, desperately sprints to a nearby motorboat and narrowly escapes.