The axial "trilithon" doorway between the apses.
A more accurate term would be "quadrilithion"
as there are actually two lintel stones, this can be seen
in our VR tour by looking directly upwards at this location. The "trilithon
is flanked at its base by two "slab altars",
pitted decoration survives on the front and side faces of the southern (left),
stone. Through the portal can be
seen part of the terminal altar and its tall southern flanking stone.
Note the "libation hole" worked in the paved sill of the portal.