まとなり
immediately adjacent
Also written 真隣り、真となり
No-adjective, Noun
食堂しょくどうはロビーの真隣まとなりだが・・・てゆーか、恵子の場所ばしょから、あと３歩ほしかないぞ？
The dining hall is directly adjacent to the lobby, or rather, from where you are, it's just three steps away?