The challenge also requires you to not be spotted, which means even if you aren’t spotted until the double kill, you will still need to finish the mission by using an exit and not to be spotted for the entire mission.
In short, try it again and finish it completely without getting spotted.
另外，我理解你无法使用 YouTube 观看教学视频的困扰，但还是希望你能使用以下讨论串来询问问题。不过若你还有其他问题的话，也欢迎你留给我私人讯息来询问喔。 