In the discussion about Torricelli's theorem, participants question why atmospheric pressure is considered equal at two points (P1 = P2). The connection to Bernoulli's Principle is emphasized, highlighting that total pressure, which includes both fluid and atmospheric pressure, must be accounted for. The role of atmospheric pressure in fluid dynamics is clarified, indicating that it influences the pressure calculations in the theorem. Understanding these pressure dynamics is crucial for accurately applying Torricelli's theorem. The conversation ultimately underscores the importance of recognizing the contributions of atmospheric pressure in fluid mechanics.