No spoiler tags need for content in this episode or any previous one. Use spoiler tags for anything from later episodes.
Sample Spoiler
If you can see this without revealing a spoiler first, your current app does not support spoiler tags. Browse these comments at your own risk.
Not saying it’s rational. That’s my interpretation from what David said. He was driven mad with grief and isolation. He doesn’t even care if Cliff would doom the mission. They either suffer together or die together. He wanted to have something no matter how twisted it is.