He knew this was coming.
She lingers at the inner door for a moment before walking towards the console, where he was fixing something he allowed to stay broken for this very purpose. She waits, patiently, for him to straighten, for him to look at her.
It has been several days, or the nearest equivalent. They've saved the world since then, and brought Tegan home. Their makeshift family has been whittled down to two, and now he must tell her why.
"The first rule of Time travel, the most important rule," he begins, and he's staring right at her but he can't bear to actually look at her, "is that one cannot interfere with their own past." His hand tightens around a tool older than them both, enough to hurt, enough to leave a mark.
Her gaze is sad, and gentle, and it inflicts a far deeper wound.
"If I...if I were to be tempted...the consequences…" He's not used to this. He's not used to stumbling over words and falling into silence.
"I wish I could," he says, finally, and the words are fervent.
"You must know that, I just – "
"Doctor." The word is soft, but firm, and she steps closer and rests her hand on his where it grips the console.
"I wanted to say that I understand." His eyes widen, and then close, as his arm wraps around her and pull her close.
It is an awkward embrace, in the way walking is awkward for those just learning, but she returns it, and they are no longer alone in their grief.