Reference for Zevachim 69:1

אף אני לא אמרתי אלא כשנתקבל בכלי והוא גופיה מנא ידע כהנים זריזין ועבדין הייא ומשתפכין

spoke only of that which was received in a vessel. And how does he himself know that? - The priests are careful; but as they work quickly [the blood] may be spilt.

Jastrow

Jastrow