Parashas Naso · Passuk 5:04
The Israelites did so, putting them outside the camp; as GOD had spoken to Moses, so the Israelites did.
Chabad.org — English translation + Rashi
Source: Pesachim 67a.
English: “So they did” — what does this teach? That even the impure themselves did not delay.
In context: The doubled language of compliance is midrashically read as including the voluntary departure of those who were impure.
Custom
Chazal teach that the impure cooperated and did not resist being sent from the camp.