The Doctor really played with fire here. He manipulated events and allowed Kleig to get to where he could awaken the Cybermen, despite all his insistence that that shouldn't be allowed to happen... just because he wanted to see what Klieg's plan was? I think he let his curiosity get the best of him there.
Oh, and brilliant suggestion, Doctor -- lock up the crazy power-mad logicians in the room full of prototype weapons! How could that possibly go wrong? Is it me, or is the Doctor basically just making everything worse?
But the Doctor choosing to re-electrify the doors seems uncharacteristically vicious for him. Killing Cybermen is one thing, but he set it up to kill any hapless archaeologists who might come across the tomb again -- and he does get Toberman killed as a result. Again, practically everything bad here is the Doctor's fault. Why not just have the expedition use more of the blasting equipment they used at the beginning and re-bury the tomb?
This definitely seems to me to be one of those episodes where the Doctor's curiosity and impish tendencies get him [and others] into a great deal of trouble... the sheepish look on Troughton's face as he admits that he just wanted to see what Klieg would do was priceless...
...my question is what the holy hell was up with George Roubicek, the guy playing Captain Hopper [who was pretty much the actual saves-the-day hero in most of the episode]? His delivery was so bizarre that it just dropped me out of nearly every scene he spoke in, thinking "wtf is up with him??" It sounded like he was halfway between parodying what a strong-willed spaceship captain might sound like and a really bad John Wayne impression. Amusing to see from wiki that he was a dialogue coach [!] and appeared in Star Wars