It is (just) a "special encounter" - Remebering (a tribute to - if you will
) Fallout 1.
IIRC the other persons talk about stuff from Fallout 1.
In that Cafe you will find a dog, if you approch him in your vault suit he will take a likeing to you. (I belive that is how)
That dog is Dogmeat - one of "your" most trusted compainions in Fallout 1.