Daleks didn't laugh; they had no emotions. Dalek Caan laughed though. It had broken through the walls of the Time War and had been rewarded with insanity and a strange ability to see future events. So Dalek Caan laughed in a way that a dalek should not be able to as it declared, "He is here, the Dark Lord is come!" Davros prepared himself to meet with the Doctor once again; he had a wonderfully evil speech forming in his mind.
The Doctor was brought down to the vault and the holding cells were activated as Davros began his speech. He spoke of the Time Lord before him and he spoke of Dalek Caan saying, "He saw time, its infinite complexity and majesty raging through his mind and he saw you" Davros decided to quote Dalek Caan "The Dark Lord he called you. Quite fitting don't you think?"
It was a rhetorical question and Davros was about to continue when he was broken out of his rant by the Doctor who had suddenly stopped looking angry and said "Ah no, not really fitting at all" Davros tried to frown to show his anger at being interrupted but it wasn't very different from his normal expression and the Doctor didn't notice. 'If the Doctor would stop blabbering long enough for him to get on with his speech,' Davros thought 'I would get to the part about fashioning people into weapons and then it would seem more fitting.'
"I mean did you seriously just call me The Dark Lord? I may have done some things that I'm not proud of but really, who in their right mind would call me the Dark Lord? It's so clichéd, a completely overused title in reference to bad guys (one of which I am not I might add). I mean look at me! For one thing I'm incredibly hyperactive. I can't stand still long enough to get a single thought out most of the time and nobody ever actually understands what I'm saying. If that's not enough for you, I also try to befriend just about every enemy I've ever had. Remember the Master? I didn't want him to die, I was going to keep him on the TARDIS with me as some sort of weird pet or something until he decided to go and die on me anyway."
"It was not me, but Dalek Caan who prophesized you to be The Dark Lord. He said 'The Dark Lord is come' and here you stand" replied Davros to the slightly overwhelming rant the Doctor had just given and still rather peeved that the inconsiderate Time Lord had interrupted the flow of his beautiful, diabolical speech.
"Now Dalek Caan flew through the walls of the time war. This seems to have given him some new and interesting abilities and did it ever occur to you that he may not have been talking about me?" the Doctor was going into analyzing mode. He tried to start pacing but only bumped into the wall of his holding cell. Rose giggled.
"Come on Davros" she said speaking up for the first time, "would somebody called 'The Dark Lord' be daft enough to bump into the wall of his holding cell?"
"Hey!" the Doctor shouted in indignation.
"Come on Doctor, it was rather silly" Rose replied as the Doctor shrugged in agreement.
"I see no one else arriving" Davros stated, trying to bring the conversation back under his control, but at that very moment Dalek Caan started giggling again.
"The Dark Lord! He is come, he is come!" The Doctor was about to start pacing again when he remembered the holding cell and refrained, instead looking at Davros and beginning to speak.
"I know that's not me or Dalek Caan wouldn't be saying it, we all know I'm here"
"Who could it be, Doctor?" Rose directed at him. The Doctor looked at her but didn't answer her question. Instead he continued addressing Davros.
"And if the Dark Lord isn't me, then you don't know who it is. Do you really want to be dealing with somebody called the Dark Lord while you have an evil plot to execute? I mean, he might have an evil plot of his own that would completely clash with your evil plot. On top of that, we all know that villains never get along with each other." Davros didn't know how to reply but was saved the effort by the shouts of EXTERMINATE and sounds of chaos coming from up above. "Now I wonder who that could be?" said the Doctor.