The Lord always saves the devotee from impersonalists and voidists. The Lord is present in everyone's heart as the Supersoul to give the living being protection and all benefits. Thus the Lord acts sometimes as the killer and sometimes as the protector. One should not accuse the Lord for any discrepancies. It is His plan that we see varieties of life within this material world. All of them are ultimately His mercy.
Although the entire cosmic manifestation is nondifferent, the material world is nonetheless different from the spiritual world. Only by the mercy of the Supreme Lord can one understand how the wonderful material nature acts. For example, although Lord Brahmā appeared from the lotus seat that had grown from the abdomen of Garbhodakaśāyī Viṣṇu, he could not understand what to do after his appearance. He was attacked by two demons, Madhu and Kaiṭabha, who took away Vedic knowledge, but the Lord killed them and entrusted to Lord Brahmā the Vedic knowledge.