Fire in the Outskirts

"Now the people complained about their hardships in the hearing of the Lord, and when he heard them his anger was aroused. Then fire from the Lord burned among them and consumed some of the outskirts of the camp. When the people cried out to Moses, he prayed to the Lord and the fire died down. So that place was called Taberah, because fire from the Lord had burned among them." Numbers 11:1-3

I tend to find question not in the mainstream of the writing, but in its perimeters. Though the message of the verse seems to be the judgment of the people's complaint, I wondered why God would simply char the outskirts of the camp. Why not the people that actually complained?

I had asked a friend in seminary, and this was an excerpt of the answer that I received. I would love to cite the source, but he had only taken a photo of the writing. I send an apology for the lack of citations to the author. 

"The Lord was merciful in sending his purging fire only to the perimeter of the Israelite camp. Many could have been consumed had the judgment been meted out in the midst of the encampment. The outskirts of the camp were where uncleanness and ceremonial impurity were relegated (Exod 19:16; Lev 14:8; 16:26,28; Num 5:1-4). A judgment of fire from the Lord often comes by means of lightning, though the mode of igniting the fire is not specified. This form of judgment parallels that meted out against Nadab and Abihu (Lev 10:1-3), though that fire came out from the midst of the tabernacle."