Transcription: A screenshot of a tweet by a user called 'llama in a dracula cape (@LlamaInaTux)'. The text of the tweet is as follows.
Flight attendant: Do we have a doctor on board?
Me: I have a PhD in Mathematics
Flight attendant: one passenger is having a heart attack and one passenger is having an asthma attack
Me: nodding That makes two
The formal logician next to him: "So we know there is at least one other passenger. Unless... are you feeling okay, doc?"