“Does sarcasm help?”
“Be a great universe if it did...”
The Husbands Of River Song coming an episode apart from Heaven Sent really shows the kind of range Doctor Who has, going total panto romp right from the start up to the wistful ending.
More removable heads? Oh, I see, they’re fans of the first one. (Although the rest of the patrons being in on it is also rather Deep Breath.)
Evening wear in a can! Good for multiple occasions and levels of formality.
A happy(ish) ending for two characters who have been decapitated. This may be a first.
The restaurant reservation bit is very Douglas Adams. (As was most of the episode.) You so would use a time machine for that.