For challenge mode the rules state it ends at click to continue it should be "click for story time". But i propose since there isn't really an ending for challenge, it should just be on the final egg click. As that is when the in game timer considers the stage complete.

Here's a link, figuring out discord as I go so bare with me lol https://discord.gg/f97bkBh

There isn't currently a discord I can make one if you want. I personally wont be doing runs for a while cause I'm busy with a new job and am changing apartments soon. I don't mind answering any questions you may have though. (See below for Discord Link)