The hechal (central room) of the bes hamikdash had its main entrance on its eastern end. To either side of that entrance were cubicles, and the main-floor cubicles on each side had a door to the east also. Thus, the eastern exterior wall of the hechal had three entranceways visible. The northernmost of these, which entered into a cubicle, was unlocked and opened every morning before the korban tamid (morning sacrificial offering) could be brought. Mishnayos Tamid chapter 3 mentions that fact, and mentions, also, that door's means of opening. While commentators differ on what is meant there — the Rav says (ibid.) that one had to reach through a hole in the wall to unlock the door from the inside, while the Rashash says that one merely had to bend over to use a keyhole near the floor — it was by all accounts an awkward way to unlock a door. I haven't seen anyone, however, explain why that door had such an awkward means of unlocking from the outside, especially in light of the fact that the door was unlocked daily from that side. Why did it?