This. I've worked past the point that my access started expiring and I had to make sure not to reboot anything important so I could keep making progress, even

This. I've worked past the point that my access started expiring and I had to make sure not to reboot anything important so I could keep making progress, even after they came and took my chair away [yes, seriously]. When I absolutely had to reboot the dev system to continue, I sent off my final notes and left. I do agree that knowledge transfer is top priority, but sometimes there's also work I'd really like to hand off in a completed, easy-to-take-on state, that will save the next engineer ever more time than another few hours of brain dump. Still, try to do the brain dump first.