4th year seniors do not show properly on the big board, the logic for them to display right is missing so it defaults to this, because most seniors graduate or something. my memory is fuzzy, but i think we know that the odds for that 4th senior leaving are the same as an equivalently ranked junior. which would put the odds for your guy in the 90-95% range or so. don't get your hopes up basically, but 5th ranked guys come back every once in a while, so its not unheard of for him to stay.