Complex sentence: Neville cautiously goes in after her and finds the deer's corpse along with Sam, but the building is infested by a colony of Darkseekers, both manage to escape unharmed and the attacking Darkseekers are killed by the sunlight.
Split into simpler sentences: Neville cautiously goes in after her and finds the deer's corpse along with Sam, but the building is infested by a colony of Darkseekers. Both manage to escape unharmed and the attacking Darkseekers are killed by the sunlight.