What would the behaviour of tearing one's clothes, letting one's hair hang loose, and shouting "unclean" symbolize?
These are all signs of mourning in the Old Testament (Ezekiel 24:17, Ezekiel 24:22; Micah 3:7). They symbolize that the unclean person is ceremonially dead. They have no access to the temple, the dwelling place of God, or the covenant community (Numbers 12:9–15; 2 Kings 7:3–14). They are cast outside of God’s presence and blessing.
45 Le lépreux, atteint de la plaie, portera ses vêtements déchirés, et aura la tête nue; il se couvrira la barbe, et criera: Impur! Impur!