Well, here we are. The Doctor came face-to-face with Setekh. And now, we see the final showdown between two ancient and powerful aliens with the fate of the human race (among others) at stake.
It does not go well for the Doctor. It would seem even he isn’t mentally strong enough to withstand the telepathic might of Setekh.
You know, that’s kinda scary. We’ve seen the Doctor in various incarnations shrug off mind control and the like so many times. And this guy is too powerful for him. Granted, Setekh is closer to a god than anything else. Furthermore, the Doctor was a bit afraid of him from the beginning. But it sure is scary to see even the Doctor fall under the control of an alien evil.
Besides, the Doctor has something Setekh wants: the key to the TARDIS. Maybe the Doctor destroyed the missile, but the TARDIS can open Setekh’s prison/Martian pyramid much more directly. All Setekh needs to do is have the Doctor deliver Not-Professor and whatever robo-mummies are left over to Mars. From there, Setekh can see through Not-Professor’s eyes and disarm all the traps. Plus, once the Doctor can dropped Not-Professor off, they can simply strangle the Doctor and leave him for dead, much to the horror of Sarah Jane.
Fortunately, he doesn’t die. The Doctor has a secondary respiratory system. Death by strangulation isn’t that easy for a Time Lord. Maybe he and Sarah Jane can get through all the puzzles and stop Not-Professor before he lets Setekh out.
Or maybe not. Horus left plenty of booby-traps, but nothing too complex for Setekh. Or the Doctor, to be honest. True, he uses the stitching on his scarf to get past one trap, but he’s too far behind. Setekh is free to travel the space warp back to Earth. That travels at the speed of light. Not-Professor dies a second time, but the Doctor, well, he has a new plan. There is one thing that travels faster than the speed of light.
That would be the TARDIS.
See, it would take Setekh two full minutes to get from Mars to Earth. He’d be vulnerable during that time. So, the Doctor simply gets back to Earth first and hits Setekh with a device that speeds up the evil god-alien’s own aging process, killing Setekh in seconds. And since the TARDIS is right there, the Doctor and Sarah Jane can skip on out before backlash causes the whole building to explode.
So, let that be a lesson to alien god monsters. You may be stronger than the Doctor, but he’s still a lot smarter.