Maybe they evacuated everybody still alive after a fire and detonations severe enough to cripple the ship. Had there been any chance to save it the crew would probably have stayed and tried to keep it afloat. Under the circumstances i wouldn`t be surprised if a large part of the crew had perished. So it may be true that everybody was evacuated AND that only fifty or thereabouts were saved.
” So it may be true that everybody was evacuated AND that only fifty or thereabouts were saved.”
And also may be true that only a skeleton crew of 54 was aboard as it was being towed.