In Shemoth 37:9 we read that the faces of the cherubim were toward each other, the faces of the cherubim were turned toward the mercy seat. Were the mercy seat at eye level between them, or did the cherubim had two faces? In Ezekiel 41:18-19 we read that there were images of cherubim on the alls with two faces - the face of a man and the face of a young lion?
Firstly, I should say that we the term "mercy seat" does not come from Jewish sources and in Jewish tradition the "kapporet" may be simply translated as a cover for the Ark. The meaning of the face of the cherubim being toward each other and at the same time towards the cover is intended to explain that the direction of their faces was in the direction of the Ark or as Ibn Ezra suggests their faces were a bit tilted downwards towards the cover.