According to Rav Elazar Ben Azarya - he makes a gezeirah shava to makas bechoros- just as there it was Chatzot- so too here its up until Chatzot- but over there at makas bechoros- it only STARTED at chatzos- and oculd have ocntinued well into morning, the maka only started at chatzos, and didnt end at that time, how can rebbe elazar ben azarya assume then that at chatzot we have to stop eating (the lashon he uses is ma lehalan AD CHATZOT, af kan ac chatzot- but over there its not AD CHATZOT)
Dovid, Brooklyn, NY
It is clear from the Sugya that Hash-m killed all the firstborn at the stroke of midnight (as only Hash-m can do). And once we know that, it is logical to say that, according to R. Elazar ben Azaryah, it is up to midnight that they ate the Korban Pesach, and not starting from midnight, since (as the Ma'adaney Yom Tov explains, they were given the Korban Pesach a. in order to prevent the Angel of Death from entering their houses, and b. so that, at the exact moment that the Egyptian firstborn were being killed, Yisrael were eating the Korban Pesach (and neither of these reasons applied beyond midnight, as we explained).
Kol Tuv,
R. Eliezer Chrysler