Flight 93 on 9/11/01

[TheWorldNewsOrg]

"Hello Mom, this is Mark Bingham" said a passenger in a phone call from the hijacked Flight 93 on 9/11. Who uses their surname when talking to their own mother???

http://www.historycommons.org/entity.jsp?entity=alice_hoglan_1

However, even his own mother appears to have found what he said bizarre. From the timeline entry:

Alice Hoglan finds it strange that he has used his full name to introduce himself. [Pittsburgh Post-Gazette, 10/28/2001] “He was so flustered, I guess, giving me his last name,” she will later comment. [ABC, 9/11/2001] “I remember being amused that he used his last name,” she will say. [San Francisco Chronicle, 9/10/2003]

[TheWorldNewsOrg]

He also made other odd comments, telling Hoglan: "You've got to believe me. It's true." What was going on here?