In the article about Engel's testimony which took place 3 weeks earlier than Cassidy, the press reporting on it, used the term Beast as well, and that Engel testified that he and Trump in the car, differed on taking him to the capitol or the whitehouse....or they had a disagreement on it.... But in the end, he brought trump to the whitehouse.
The secret service among eachother, do not use the term, The Beast, when talking about the Limo, involved with their work, they call it, Cadillac One.... It is the public's and journalist term for the President's vehicle that he travels in.