Meron tragedy - dispute between Amoraim

 Pesachim (64b) THE FIRST DIVISION ENTERED etc. It was stated, Abaye said: We learned, ‘They [the doors] locked themselves’(Or, were locked-miraculously, without human agency.); Raba said, We learned: THEY LOCKED. Wherein do they differ? — They differ in respect of relying on a miracle. ‘Abaye said, We learned, They locked themselves’; as many as entered, entered, and we rely on a miracle.( That the doors should shut themselves when sufficient had entered) Raba said, We learned, THEY LOCKED, and we do not rely on a miracle. 

In this way the Paschal lamb is slaughtered in three groups of thirty people each, although the total number of people involved is only fifty.

The mishna teaches that the first group entered, after which they closed the doors to the Temple courtyard. It was stated that the amora’im disagreed about the precise wording of the mishna. Abaye said: We learned in the mishna that the doors of the Temple courtyard miraculously closed by themselves. Rava said: We learned in the mishna that people would close the doors of the Temple courtyard at the appropriate time.

What is the practical difference between them? The practical difference between them is with regard to whether we rely on a miracle. Abaye said: We learned in the mishna that the doors closed by themselves; as many people as entered, entered, and we rely on a miracle to close the doors so that an excessive number of people not enter and thus create a danger (Rabbeinu Ḥananel). Rava said: We learned in the mishna that people would close the doors, and we do not rely on a miracle to ensure that the courtyard not become overly crowded.