Sometimes, the only available cover is another person — be they a terrified member of the public or a life-long friend.
Characters who use human shields treat them as cover, with Durability equal to the victim’s Stamina + any armour.
Unlike normal cover, the victim takes all of the damage from the attack.
Using a human shield is almost certainly a Breaking Point or Act of Hubris.
For a Sleeper, this means a pretty severe modifier (–3 or more) if the victim dies; mages face an Act of Hubris at Enlightened or Understanding Wisdom.