"Picture the most popular Doctor from the original series, Tom Baker, saying this..."


Yeah, it just doesn't work. He'd never ever say the "if you value your continued existence, if you have any plans about seeing tomorrow" part. If he'd just escaped from a trap and somehow foiled the bad guy's plans in doing so and was explaining to Romana how he did it he'd probably say the rest of it, sporting a huge grin as he did so.
If he was ever in a position where the bad guy was about to put him in a trap and was threatening the Earth he wouldn't say anything like that.