Lisp doesn't really have separate release/debug modes[1]. When you want to distribute a program as a binary, you dump the image and set a custom top-level function to use instead of the default REPL. The program will still contain the compiler/interpreter and can redefine everything just like during development (altough the program might not use or expose those features to the user). The REPL isn't in any way magical in Lisp; it's just the default option for interacting with the Lisp.

[1]: You can ask the Lisp to drop all debug information as an optimization, which makes development impractical, but still possible. Some implementation might allow you to distribute a program without the compiler, but the standard does not specify that.