Hurrying to catch up with the others, Donna and Karanga came up behind the Doctor and River. He was gesticulating wildly. "Yes, but how did you get tangled up in all this?"
"I really can't tell you that, dear."
"Gah!" He stomped onwards. "All right, well, can you at least tell me what you've done already to help?"
"Analysed the captured nanobot, created a reader that unpacks its programming and commands, and set that to processing while we came to get you. That do for starters?"
The Doctor stopped in his tracks. "What? You called me here - will call me here - because of a lone nanobot? You realise I can make all of this never happen."
"Oh? How's that, then?" River's voice was heavy with sarcasm.
"Easy-peasy. I just won't tell you how to summon the TARDIS."
"Really, Sweetie, I thought you'd know better than that." She flicked open the heavy leather console on her wrist and slowly began to tap and twist its controls. "I guess I didn't learn that from you. Not today, anyway. Besides, I'm the one who can still make this unhappen. I haven't decided yet if I need you. So if I never make the call..." She flipped the lid shut. "Zip. Nothing happens. Although, since you're here, I obviously do decide in the positive. Always lovely to see you, anyway." River reached over and fondled his chin with a soft laugh and he jerked back, speechless and scowling as he rubbed it.
Donna was trying to make sense of the strange exchange when she heard a sound beside her that might be throat-clearing. She looked down. "They have known each other a long time?" asked Karanga.
"Actually, I'm not sure," said Donna. "Sometimes it seems that way, but he's always surprised to see her." And she's supposed to be dead, she thought, but didn't say. Some things were just too weird to share with someone you just met, even if that someone was an alien pretending to be a bird and thus should generally have no problem with weirdness.
"Time travellers," said Karanga. "Easy for things to get muddled up."
"I suppose." Donna decided she'd have to consider it later. She bent to step through a gap between two leaning branches, and gaped at the sight of the Doctor vanishing calmly into a large doorway in the hillside.
The kiwi birds followed after him, all except Karanga, who waited patiently at her side. "This is our base. You will be safe here - and this is where Mrs. Song has set up the machinery."
"Mrs. Song, hmm?" Donna stuck out her lower lip and nodded slowly. "So she's married," she muttered to herself. She'd save that up to tell the Doctor later, assuming she ever got him to herself again. The way that woman just wrapped him around her finger! Well, Donna was certainly not averse to giving him a dressing-down when he needed it, but not in a way that suggested she wanted him. Ewww.
"Enter, please," said Karanga, and pointed with her beak at the dark hole.