The text plays on the computer command prompts that typically offer options like 'Abort', 'Retry', and 'Ignore' by replacing the last option with 'Panic', which humorously suggests a human reaction to a computer error rather than a computer command. It also exploits the similarity in format to the usual computer prompts, creating a pun based on the unexpected substitution of a word.
Backup not found : ( A ) bort ( R ) etry ( P ) anic