I agree with most of the criticism here. Much of the episode felt like a retread of The Zygon Invasion/Inversion and Dark Water/Death in Heaven - in each case the Doctor is summoned by UNIT because of a great crisis, declared president of Earth, but the problem is so great all the Doctor winds up doing is pacing in a room with some officials. And that worked more or less the first time because Missy was on the plane too so there was a sense of immediacy and danger. But here the tension only came from the doomsday clock messages, and the knowledge that something was going to happen in the biochemistry lab.
And it's not bad, but compared to the last few episodes, it's not great, especially keeping in mind that we've had a similar story every year since Capaldi came aboard. That last act was stellar here, doing a great job of ratcheting up the tension and giving the episode the stakes it sorely lacked before that point.
I wouldn't be opposed to a running gag of Bill getting Penny back to her place only for someone else important to come barging out of her bedroom every week.