To survive beyond 1 Gy from now, life will need to move underground where the water is and hopefully much cooler than the eventual surface. Also, such life may/will become necessary to relocate to Mars, hopefully taking resources with them. (I don't say "us" because of likely dramatic evolution.)
The only reason that the subsurface rock is cooler than magma is being able to conduct heat through to a cooler surface. When that surface becomes exterminatingly hot and remains so for a while the subsurface will be heating up too. Since the sun is estimated to remain a red giant for about one Gy it will become hotter than the surface.
Completely in line with our propensity for destabilizing harmonic systems in nature. Imagine we do that and all of the other planetary orbits degenerate or become dangerous.
