this is, btw, probably extremely fulfilling for this dog.
Dalmatians were supposed to be hunting dogs at the founding of the breed, but what they mostly became bred and used for was carriage dogs.
A carriage dog is a dog whose job it is to run alongside a horse and carriage and prevent anyone from interfering with it. They were excellent carriage security. Nobody could reach up and grab the horses reins, nobody could try to open the carriage door - you could even park with peace of mind
This is also how they became known as firehouse dogs, because fire trucks used to look like this
and i imagine having a carriage dog was very useful to prevent even well-meaning members of the public from doing anything stupid to the equipment or horses while you fought a fire.
So the dog in the video is probably feeling very Job Well Done about his activity