Did you realized, Unnoticed gunshot sound ? [SPOILER]]
When the bodyguard entering the final room to meet the boss. Just before, he walks like hallway, at first guy he shot, he walks to shot the 2nd guy in leg.
Did you realize about the 2nd guy ?
He walks calmly like there's nothing to worry about, meanwhile in some seconds before there's a gunshot of his friend in front of him with really loud sound.
:D