the atheist would probably be like....
"What the hell took you so long? All my life I've forlorny searched for meaning and truth in this puzzling universe and NOW you come to prove your existence just as i'm about to be lunch for one of your creatures? Some God you are.....!"
And God was terribly upset, it'd been a long time since anyone criticised him. Heaven was full of god fearing people who would never dare..... wait, NO one had ever critisied him!
God was enraged, in a tantrum he brought about the apocalypse.....