A portion of an interview from the linked website:
Did you realise this could be a historic moment?
Kline: No, I certainly didn't at that time.
Duvall: Not really. It was another step forward in the larger context of the work we were doing at SRI which we did believe would have a large impact.
When Samuel Morse sent the first telegraph message in 1844, he had an eye for drama, tapping out "What hath God wrought" on a line from Washington, DC to Baltimore, Maryland, US. If you could go back, would you have typed something more memorable?
Kline: Of course, if I had realised its importance. But we were just trying to get it to work.