YOU SAID:
Everyone already left
INTO JAPANESE
誰もがすでに去った
BACK INTO ENGLISH
Everyone has already left
INTO JAPANESE
誰もがすでに去っています
BACK INTO ENGLISH
Everyone is already gone
INTO JAPANESE
みんなもういなくなった
BACK INTO ENGLISH
Everyone is gone
INTO JAPANESE
誰もがいなくなった
BACK INTO ENGLISH
No one is gone
INTO JAPANESE
誰もいなくなった
BACK INTO ENGLISH
No one is gone
That didn't even make that much sense in English.