Correct. He - I do not think unjustly - has long had AGI as the goal. "Solve AGI, then use AGI to solve medicine, and physics, and the rest of science, and create a better world." has been his thing basically forever.
"Hassabis told him to add another potential threat to the list: artificial intelligence. Machines could become superintelligent and surpass us mere mortals, -perhaps even decide to dispose of us."
You're right that the picture is more complicated than I wrote above. Quickly looking, it seems that Shane Legg was concerned very very early on. I can't find anything tangible about what their strategy was to avoid the danger. It looks like Hassabis had longer timescales than Legg, so perhaps just thought they had more room before it really mattered?
