"Each man is to take his fire-pan and put incense in it—250 fire-pan in all—and present it before Hashem. You and Aaron are to present your fire-pan also." (Numbers 16:17)
Many commentators ask why this test with Qorah and his group of 250 men consisted of using the Qetoret. Were there not other ways to determine that Hashem had chosen Moshe and Aharon to lead the people?
Rashi explains that the Qetoret was chosen because it is a service that Hashem desires above all others, however, it contains the potential for death. Nadav and Avihou the sons of Aharon died when they offered an "esh zara", a qetoret that Hashem did not command them to offer. Moshe wanted to use this special double-sided service offering to test Qorah and his followers.
The Meshech Hochma offers a beautiful answer to why the Qetoret was chosen. If one notices carefully, the followers of Qorah were "Nesiim" the exalted princes of the tribes, all attested to in the text as being "important individuals". Yet, if we turn back to parasha Naso, we see that the Nesiim offered sacrifices for the dedication of the Mishkan, and of those sacrifices was the Qetoret. These very Nesiim saw Nadav and Avihou die because of the Qetoret and yet theirs was accepted. From here their error and miscalculation was based. This is why Moshe chose to use the Qetoret as a test.
Many times those who act in aggression or in anger are justifiable in their own minds. They are basing their actions on seemingly logically progression. Moshe, in his brilliance, realized that their error and haughtiness was founded on the acceptance of their qetoret in the past, and decided to prove to them with that very qetoret, that they were not the chosen ones to lead the nation.