Generally we are reading about the tragedy of Nadav and Avihu, the two sons of Aharon who died during the inauguration of the Tabernacle, just before the Holocaust Memorial Day; in both cases it's very hard to understand "why" it happened.
It may teach us that, even if we have the very human tendency to "understand", sometimes, although very frustrating, it's impossible and nothing really explains it. It challenges our faith and may lead us to look for "explanations" which are mostly unsatisfactory.
All we can do is try to look for the meaning of the tragedy in our life.
Shabbat Shalom to all,