I think the beginning of a story based game is very important, and to me this prologue doesn't make sense. Without any context, the MC is told about the other universe and that he will be going there on a mission, all within a few sentences, and then he is immediately in the "prime" universe. I think it would work better if he either accidentally gets transferred or is forced to go.
If you want to make him part of a "mission" to the other universe, you should at least imply that he was in on the research and aware of what they were trying to do. Not just "we found another universe and we are sending you there".