I've been reminded of my Tank Ending to Faux Pas, in which the following happened to Lex:
Lex Luthor, who had been inspecting his underground hideaway at the time, was spared the sudden and painless death those who were in the immediate target range suffered. However, his curiosity piqued by the noise and shaking, he ventured above ground once things had quietened, and he was quickly burned to a crisp by radioactive flames. His last words are believed to have been, “I knew I should have funded that madman Klein’s research into the cause of Superman’s invulnerability!”
Wendy