Let's say that each person in the world is conscious and their experience can be viewed on a video. Then let's introduce an additional giant movie theatre screen, and call it "Me". In this case, the screen represents the current present experience that is being played here and now and observed from the centre of reality from a first person point of view.
The question is what video is playing on the giant screen? One answer may be that it is Siamii's video (who is the author of this post). That would make Me become Siamii. As you can see, there is a single assignment of first, selecting a video among a collection of video experiences in the world, and second, putting that video on the giant screen, making that experience become THE observed experience. Initially, each video is private to each person, but by putting one of them on the screen, that one becomes the video that is being playing in the present moment, which means that experience becomes "My" experience, and Me becomes that experience.
In short, this illustrates the difference between the two sentences, "Siamii is Siamii" and "I am Siamii". Even if both of these sentences happen to be uttered by Siamii, they have materially different semantic meanings. While the first sentence is a tautology, the second sentence signifies the fact that Siamii's experience has been selected from a collection of experiences to be the present one, and his experience has been put in the centre of perception on the giant screen, and this way it has become "Mine". The first sentence assumes that the centre of perception is somewhere else other than at Siamii's location, and not playing on the giant screen.
There could be a few more scenarios to explore regarding the giant screen. For example, it could be that no video is playing on the giant screen. That would imply that Me doesn't exist, either not born or dead. However, it may well be that Siamii still exists, and is conscious and has their own experience, but that would entail Siamii is not Me. Another possibility, that Me is playing some other video, for example Bob's video. In the video you can see that Bob is watching TV. By putting that video on the giant screen, it would mean that Me is in fact Bob and Me is watching TV. Hence Me is not Siamii. Yet another possibility, that there are multiple videos on the giant screen, sort of in a split screen mode. That would mean that Me is multiple experiences at the same time, so Me would be multiple people, sort of in a superposition of identities.
Going back to the first scenario, we know that the giant screen is in fact playing Siamii's video. How do I know that? Because the present experience is from Siamii's point of view, which implies that Me is Siamii. This is known, because Me exists as Siamii. However, now I ask Bob, what he thinks is playing on the giant screen? To my utter surprise, Bob claims that on the giant screen it's actually Bob's video playing, not Siamii's. That's because according to him, Me is Bob.
We seem to have a conundrum. We know that although there are multiple videos in the world, corresponding to each person's experience, in fact there's only one giant screen that plays the present experience. That's because the present reality is experienced from a single point of view according to the existence I see. Bob doesn't deny this and agrees that even though each person has their own experience, only one of those experiences is "centered" here and now, which is what the giant screen shows. What he disagrees about is which one.
So how can the giant screen both show Siamii's and Bob's experience? Since Bob and Siamii both live in the same world, and they both claim to have a single giant movie screen, how can they both be correct? Since I do in fact exist as a present centered experience, which is the essence of my own being, I know as a result that Me exists as well, and I also know that Me is assigned to Simaii's experience. So I know without a doubt that Bob is lying. That or the world has a pretty obvious contradiction, where a given entity, called Me, actually seems to take on two different values, Siamii XOR Bob, while existing in the same shared reality as Siamii AND Bob. How could this logical contradiction be resolved?