Duty period

Duty period means the period of elapsed time between reporting for an assignment involving flight time and release from that assignment by the certificate holder. The time is calculated using either Coordinated Universal Time or local time to reflect the total elapsed time.

Since the time after 14 hours does not require flight time (have you have been released from the assignment involving flight time? I say yes), you may work beyond the duty period so long as it does not involve flight time but you must get the required 10 hours uninterrupted rest before the next duty period.