"I still don't see why you had to slap me," the Doctor proclaimed. "You, snogging another blonde after crooning over—" Christina stopped herself. The Doctor didn't know that she had read his journal. She flipped her hair back and cleared her throat.
"Anyway, where's the magical TARDIS going to take us?" Christina asked. "Home. So basically, to 21st Century Chiswick, London for some shopping," he replied. "More shopping? Come on! This isn't all for groceries is it? Aren't you going to tell me?" the Doctor ignored her.
The TARDIS rocked back and forth again, but this time Christina wasn't looking forward to it. Home. She was wondering whether "going shopping" was just an excuse for him to drop her off. Or maybe he'd leave without her. She shook her head. That was too manipulative and sick for the Doctor. And with that, she trudged outside with a worried and troubled mind.
The Doctor strutted out the door, seeing the look on Christina's face. He told her that they'd meet in front of the TARDIS in an hour. He began walking to the shops. He found what he was looking for, then went to the counter and waited to pay for it. "Paper or plastic?" a familiar voice asked. He looked up. In front of him was a red-head wearing a classic BuyMart blue collared shirt. "Err… plastic," he replied. Donna looked at him again and said, "Wait. I know you." The Doctor looked alarmed.
"Really?" he said. Donna nodded her head. "Yeah. I never forget a face. I know! Your that John Smith bloke that visited my house," she said. The Doctor could feel his eyes being filled with tears. "Well, it was good to see you again, Donna," he finally spat out. Then he ran outside to leave a confused temp in the midst of seeing a Time Lord with two hearts broken, tears in his eyes.
The Doctor ran into Christina. "Hi… what's wrong?" Christina asked, concerned. The Doctor wiped his eyes. "Nothing. I did my shopping. Let's leave." Then he stumbled into the TARDIS, and sighed. This was the price of companions. They break your heart. Both of them.