I'm still not entirely confident in my analytical skills for Doctor Who after being totally thrown by much of last series, but I'm pretty sure this was really good... wasn't it? At least the dramatic, emotional bits were really good, and Donna is proving to be a brilliant companion for this Doctor in particular, who "used to" have so much mercy, remember. He needs someone, and the someone he needs right now, when he's a bit confused, still grieving for Rose, and still feeling guilty over Martha, is Donna. He needs a strong hand, and he certainly gets that with her. I've got to say that I was *very* happy when she told him not to tell her to shut up. Damn straight.
There were a couple of brilliant scenes: when Donna and the Doctor's identities were revealed by the soothsayers; and when the volcano was erupting, and Donna begged Pompeii's citizens not to head to the beach - and the Doctor not to let them all die. In the first, everyone viewing the show must have been tripped up by the announcement that Donna has "something on her back", but - just as Derren Brown knows - it was forgotten as soon as it was said (though not by Scott). It's an odd, deliberate thing to say, and it must have significance in the future.
The Mill did a good job with the Magma Men (as I've decided to call them because I can't be bothered to look up their names), but the sci-fi part of this episode was, I think, weak in comparison with the drama, delivered wonderfully by Tate 'n' Tennant. They're one hell of a partnership, and what the show needs, as well as the little lost Doctor.