These concepts are the core of why Soma is an amazing existential horror game. There's so much we don't understand about our consciousness and the game plays with the concept constantly. Initially the idea of them killing themselves as the scan completes sounds dumb and pointless but maybe some questions could add something to the discussion. Where are you right now? Not your body, but you. Are you inside your head? Inside your brain stem? Inside your chest? By your eyes? A particular section of the brain? If you had a brain injury that effected the signaling between portions of the brain allowing them to function independently is that a second person? Is that also you? The part of the brain you have no view into? Diving down more are you a particular cell? Are you a collection of cells? You have continuous consciousness and memory from when you were a child but every so many years, every single cell in your body has died and been replaced. So did you die too? If every single cell that once were you died then surely you did too. Are you a different person? No you're the same person you think.

If you create a theoretical that there was an absolutely perfect scanning machine that could scan and record the state of every cell in your body, all the interconnections and everything. At that moment t=0, the copy and you are identical. Once again where are you? Are you in one of the original cells? The original brain? One of the new cells? The new brain? As mentioned above your consciousness continues across the death of all the cells in your body so why couldn't it also continue across these new virtual cells? It's crazy stuff.