Mark is a character who appears in Dying Light. He is a resident of The Tower, and is rescued on the thirteenth floor by Crane during the "Awakening" quest.
Mark was visiting his brother, who was presumably quarantined on the floor due to a bite, only to find his brother had turned. He barricaded himself in an apartment bathroom, cutting his arm in his rush to escape from his former brother. Crane comes to the thirteenth floor to search for him, kills his brother, and bandages his wound until Lena arrives to take him to the sickbay.