This app was mentioned in 3 comments, with an average of 1.67 upvotes
https://play.google.com/store/apps/details?id=com.mobication.EggTimerPro.AdFree&hl=en
Begins To Set or Partly Set - Simple enough... Pull the egg and put it in ice bath for a moment to stop cooking.
I've had nothing but success with this app: https://play.google.com/store/apps/details?id=com.mobication.EggTimerPro.AdFree&hl=en_US
I've used this for years. I love soft-boiled eggs.
https://play.google.com/store/apps/details?id=com.mobication.EggTimerPro.AdFree&hl=en