Continuity mistake: Just before Kate asks Rabb if he was a pilot she starts to take a drink from her cup. The shot changes she starts to take a drink again. (00:38:30)
Continuity mistake: When Rabb & Kate arrive on the Seahawk, they are not wearing the proper life-vests, etc.
Answer: Officially, the individual has been ordered to attend, failing to could be interpreted as either, Failure to follow orders, dereliction of duty, going AWOL, or even desertion. It would depend on the underlying reason as to why the person doesn't appear.