Parashas Acharei Mos · Passuk 17:04
Chabad.org — English translation + Rashi
Torah Temima points to Kiddushin 57b.
English: Karet applies to a consecrated animal slaughtered outside; ordinary chullin slaughtered in the azarah do not carry karet.
Korban vs. chullin
The severe penalty is reserved for treating a korban as if it were outside; chullin killed in the courtyard is a different (lesser) prohibition.