Continuity mistake: For most of the scene where the Doctor and Donna find the dying Ood Delta-50, the front of his body is covered in snow. After he mentions "the circle", when the Doctor is asking what that is, the snow on Delta-50's chest is gone. In addition, the Doctor's hands change position between shots. (00:06:25)
Continuity mistake: During Donna and the Doctor's conversation with an Ood at the reception who she approaches to ask if he's all right with being a servant, in shots facing the Ood, he's holding his translator ball higher than he is in wide shots and shots facing Donna. (00:11:50)
Continuity mistake: During the first scene in Warehouse 15, when Dr. Ryder puts his hands on the railing as he looks over it, the exact positioning of his right hand changes between shots. (00:15:05)
Continuity mistake: When the Doctor opens a shipping container full of Ood and he and Donna stand in the entryway, he only opens the right-hand door, leaving the other one shut. In a shot from behind the two of them, facing into the crate, the left-hand door is now wide open. (00:17:15)
Continuity mistake: When the Doctor and Donna enter Warehouse 15 and see the Ood Brain, the Doctor rests his hands on the railing with his right hand off to his side. In shots from above and behind him and Donna, his right hand is closer to him. (00:35:30)
Continuity mistake: When Ood Sigma steps in front of Mr. Halpen while he's holding the Doctor and Donna at gunpoint and suggests he have a drink, the glass Sigma holds up is empty, despite the fact that he was heard pouring Halpen's tonic into it just moments before. In a shot later in the scene, the glass is shown full. (00:37:30)
Chosen answer: 1) When Stephen Moffat took over he ignored a lot of what had been developed before (there is not in-universe answer). 2) It would have killed Rose, so the Doctor absorbed the energy. His body regenerated before the energy could do a significant amount of damage that would prevent regeneration.