To quote a fellow traveller, “The day you choose to wear full plate and strap a shield to your off hand is the day you announce to the world you are expendable.” This may sound harsh, but the bottom line is, when you are a group’s walking (shield) wall, that means by definition your role is to absorb hits and prevent the more vulnerable from getting injured. And yes, depending on the situation, that might include staying behind or blocking a door or hallway in a last stand to allow the rest of the group to escape. It does not mean being deliberately suicidal, however.