I think I get it, thank you. Also I read in another forum that である means "to be/is". I didn't know this before. So こんなに急ぎである =
to be in such a hurry, somebody
is in such a hurry. So, こんなに急ぎでない = someone is not in a hurry. And then なければ makes it conditional -> "if" or "when".
So basically my problem was that I didn't know the form である
