Long ago, He Xing asked Fu Han if she wanted two bodyguards, but she refused.
She felt that she was not Mr. He, nor did she want to be a pampered lady with attendants, and she disliked having someone watching her every move, so He Xing eventually compromised, only asking two mercenaries to follow Fu Han from a distance. Yet, he never expected that even such measures would fail to prevent an accident.
Those two mercenaries were actually stationed outside the company building where Fu Han worked that day because typically, no incidents would occur inside. If they were too conspicuous inside, they would attract too much attention, so they always patrolled outside the building when Fu Han was at work.
If... if He Xing could have persuaded Fu Han to let them follow her closely on a regular basis, perhaps this situation would never have arisen.