My understanding of events in Reno is that FBI SAC Red Campbell entered the plane first by the stairs. Once he ascertained Coop was gone, then the crew left. Then Campbell's team of three other agents boarded. After that, I don't know.
This scenario suggests that Rataczak left he airplane before the dogs went aboard.
Also, Tina's statements on the History Channel docu, if I recall accurately, suggests that she left the plane alone, and then stood by herself on the tarmac for several minutes - by one of the runway lights, "as I had been instructed in our training." So where was the FBI, Rataczak, Scotty, Anderson???
Calame and Rhodes clearly show how confusing this all was in their book: DB Cooper - The Real McCoy.