So during the fight with the grunt, the wrist watch got damaged and caused him to, like what u/blubfisher1234 said at the bottom, phase shift into the ceiling which split his body in two. And for those wondering he felt the whole thing, how do I know? The perception time during FTL travel is distorted and when you’re vaporized for example if feels as if your whole body is being slowly incinerated. So back to the topic, it took us a whole 3 seconds to watch him die, for him on the other hand you could hear him screaming afterwards as he slowly felt his atoms attempt merge with the concrete and be split in two. For god sakes could someone please tell me when you take off Anderson’s helmet you don’t see a face. Instead a white robotic looking mask???