Let \( \vec{a}, \vec{b}, \vec{c} \) be three vectors with magnitudes 4, 4, and 2, respectively. If \( \vec{a} \) is perpendicular to \( (\vec{b} + \vec{c}) \), \( \vec{b} \) is perpendicular to \( (\vec{c} + \vec{a}) \), and \( \vec{c} \) is perpendicular to \( (\vec{a} + \vec{b}) \), then the value of \( |\vec{a} + \vec{b} + \vec{c}| \) is: