The door of the middle chamber [was] in the right side of the
house
The south side of it:
and they went up with winding stairs into the middle [chamber];
which were outside the chambers, and which winded about for the sake of taking up less room, and which led up to the door of the middle chamber, on the south of which they went into it; according to the Vulgate Latin and Tigurine versions, they went up in the forth of a cockle, or the shell of a snail; in like manner as was the ascent of the temple of Pan at Alexandria, as Strabo F21 relates:
and out of the middle into the third;
the third chamber, and by winding stairs up to that; and the like might be on the north side, though not expressed, and on the west: the Jews say F23, that in the second temple, these winding stairs went from the northeast to the northwest, whereby they went up to the roof of the chambers, and so to the south and west; with this compare ( Ezekiel 41:7 ) ; and which may represent the windings and turnings of God's people in this present state, their many afflictions and tribulations, through which they pass from one state to another.
The Brenton translation of the Septuagint is in the public domain.