There is a secret variation of The Sun ending in which V and Silverhand storm Arasaka Tower all by themselves. To get this ending, you need to choose a specific dialogue at the end of the Chippin' In quest. During the conversation with Johnny in the oilfields choose the following (the rest doesn't matter):
- "Nah, fucked that up too."
- "What do you want from me?"
- "Ok. But as second chances go, this is your last."
After choosing that last dialogue, Johnny's affinity will go up to 40%, and the secret ending will be unlocked.
Note: Only this dialogue will work. Choosing the other ones or having a higher affinity by doing the side quests won't change the outcome. As long as you get that 40% during that specific dialogue, you can do any quest you want, even if you choose to go directly to Hanako after finishing Chippin' In.
Whenever you decide, proceed with Nocturne Op55N1. On the rooftop with Misty, after the small talk with Johnny, you'll be given the option of asking Hanako (or Rogue and Panam if you also finished their quests) for help. Don't proceed with any of the possible choices and wait patiently without doing anything. After roughly 5 minutes, Johnny will take V's silence into consideration and offer one more option. This will trigger the quest (Don't Fear) The Reaper in which V and Johnny take part in a "suicide run" by walking through the front door of Arasaka Tower and taking on the enemy alone.