It would be freaky if you opened the door and there was someone (standing) there. If there were someone sleeping there, it would be even scarier.
ーIt would be freaky if you opened the door and there was someone (standing) there. If there were someone sleeping there, it would be even scarier.
「ドアを開けて誰か（立って）いたら怖いよね。誰かが寝ていたらもっと怖いよね。」
It would be freaky if... で「もし…なら怖いよね」という言い方です。
it would be even scarier で「もっと怖いよね」
ーI think it would be kind of shocking if you opened the door and someone were there and if someone were sleeping in bed, it might be even more frightening.
「ドアを開けて誰かがいたら驚くだろうね。で、もしベッドに誰かが寝ていたら、もっと怖いだろうね。」
it would be kind of shocking if ... を使って「もし…なら驚くよね」と言えます。
it might be even more frightening で「もっと怖いかもしれない」
frightening で「ぎょっとさせる・驚くべき」
ご参考まで！
カナダ 
