She begged him not to go. He insisted that it was his debt to them. It was their only chance of continuing their near extinct race. It did not make sense to her why he always had to put himself in danger, even if it cost him his life. If he were any other person, she would let him go without much hesitation. But he wasn't disposable like that. They had just met again and now they were being once again, torn apart. They both knew there was no chance he would come out alive, and even if he did he wouldn't live long afterword.
This was always like him, not ever thinking about himself. It's what she loved, and what she hated about him. It was always good for him to be selfless and to care about others, but what about those who care about him? Do they get a chance to save him for once? If it were up to her, she'd throw herself into that fiery pit instead.
She begged him not to do this once again, knowing that her arguing would be useless. She cried and kicked, she didn't care how childish she looked she would do anything to keep him from leaving her. He told her it would all be okay. They then exchanged one long kiss, and that was the end. He quickly went and closed the door behind him. It pained him to hear her screams and cries, more than any flame.
He stepped on the platform and pulled the lever and that was the end. He descended on down to do what he must. To meet his fate.
She heard his agonized cries. If he didn't lock the door behind himself, she would be down there in a heartbeat to make all the hurt go away. She curled up in a ball next to the door sobbing. Mourning the loss of her friend and love. Damon came down to find her gazing into nothing with a glazed over expression, her face puffy from tears. Neither one had to say anything.
He tried to get her to leave, but she resisted. He knew members of the guard be sent down by the Castellan soon and he'd rather save the trouble. But he didn't want to force her to do anything she did not wish, not yet at least.
He doesn't know how long they sat there but it was definitely quite a while. He was pleasantly surprised that the castellan had not sent any of the guard yet. Though then they heard the sound of machinery moving about. Damon told her not to get her hopes up, but he was secretly wishing for the impossible as well.
He knew it wasn't possible, the flames down there were so wild that there was not even a chance of being able to regenerate. Though he was gladly mistaken when he heard the door in front of him being unlocked. He stood up ready to greet the Doctor. As the door swung open, he just stood there for a moment. His clothes were burnt and he obviously was very hurt, but he was alive and smiling that goofy smile. He looked at Romana and said "See? I told you everything would be okay." And then just fell on the floor.
Damon checked for a heartbeat and found one quite easily. "Don't worry he's still alive, just passed out. Let's get him to the infirmary before something bad does happen."