Read John 18:16 Using Other Translations
But Peter stood at the door without. Then went out that other disciple, which was known unto the high priest, and spake unto her that kept the door, and brought in Peter.
but Peter stood outside at the door. So the other disciple, who was known to the high priest, went out and spoke to the servant girl who kept watch at the door, and brought Peter in.
Peter had to stay outside the gate. Then the disciple who knew the high priest spoke to the woman watching at the gate, and she let Peter in.