"How, then, will it be when the angels take them in death, striking their faces and their backs?" Al-Hasan's interpretation is: "The angels take them in death" refers to their being gathered to the Fire, "striking their faces and their backs" in the Fire.
Muhammad said: The meaning is: How will their state be when the angels do this to them?!
﴿فَكَيْفَ إِذَا تَوَفَّتْهُمُ الْمَلائِكَةُ يَضْرِبُونَ وُجُوههم وأدبارهم﴾ تَفْسِير الْحسن: ﴿توفتهم الْمَلَائِكَة﴾ حشرتهم إِلَى النَّار ﴿يَضْرِبُونَ وُجُوهَهُمْ وأدبارهم﴾ فِي النَّار.
قَالَ محمدٌ: الْمَعْنى: فَكيف تكون حالُهم إِذا فعلت الْمَلَائِكَة هَذَا بهم؟!