Twelve hours! The Doctor said they’d been gone twelve hours! For a Time Lord, his sense of time is unbelievably bad. Twelve hours? Try twelve months. That’s how long she’s been missing, leaving her mum worried sick wondering what happened to her only child, imagining the worst.
Guilt hits Rose like a punch to the gut. She’s been off having a lark, travelling the universe with the Doctor, enjoying the best time of her life while her mum’s been going through hell.
“I meant to phone. I really did. I just forgot.”
No amount of apologies will ever be enough.