Containment vs. Liberation is the central concept of the Day of the False Master: the Labyrinth is not a “prison” but a “magical container” for an infraplanar creature.
The initial assault on the Temple was an attempt to release it. The wood, a “magical anchor”, is the Wooden Fragment with Pentacle, removed on that day.
The Templar Order was historically accused of worshiping Baphomet, a demon lord of the Abyss. In the Templar phase, the Labyrinth was possibly a Templar construction built to contain a demonic entity under sealing rituals.