Before the Doctor and Clara went off to explore their temporary home for the next few days, he decided to run back and do some last minute 'making sure you're okay dear I am so sorry you know it isn't my fault that we landed here' checks.
He stopped short when he saw a familiar shock of red hair near his box. His face fell, hearts breaking. No. It was impossible. She couldn't possibly have been there. She was home, in London, married and happy, having completely forgotten about him. For her own safety. As much as it had killed him to do it, as much as he needed his best friend, he didn't want to lose her. So that meant taking any and all memory of him away.
For a moment, he was worried that she'd recognize him, then he remembered. He didn't look the same. He could risk it. He'd definitely have to risk it if she continued snooping around the TARDIS.
"Excuse me? Can I help you?" He asked, approaching her quickly.