Need to Know - S8-E7
Factual error: Those that have a technical background may have noticed at the end, when the sub was destroyed due to being crushed from the water pressure, it was shown as having EXPLODED, instead of IMPLODING. This was due to the cost of setting up a shot, when stock footage was already available.
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.