And the kohen shall dip his finger from the blood… before the curtain… and he shall take the bull outside the camp and burn it as he burned the first bull.
Source
Sifra, Vayikra Dibbura deChovah, Chapters 6 (on 4:17, 4:20–21).
English: “Before the curtain” — just as “before the curtain of the holiness” there means aligned with the space between the ark-staves, so here. “So shall he do” — like the procedure of the anointed’s bull. “Outside the camp” — outside the three camps. “As he burned the first bull” — if both are waiting, the first takes precedence in all services.
In Sifra: Community chatas blood is aimed at the same spot as the anointed’s; the whole service copies the first bull; the carcass leaves all three camps; and when both bulls are ready, the earlier one is worked first.