Ignoring the well-being of others for the sake of his desires is practically the definition of selfishness. Which is exactly what he is doing. His actions are basically saying.
Originally Posted by ashher
"I don't care about anything as long as I can create my dream world."
That's arrogant and selfish. I mean, think about why he is creating this illusionary world in the first place? Because the girl he loved got killed, which sucks, but being willing to risk the lives of everybody Rin herself loved to do it shows who all this is really about. Himself.
His whole motivation is just "me, me, me.". It didn't come across as grand or impressive it's just a little kid throwing a tantrum because things didn't go his way. At least that's how it came across to me.