This screen has a big, red button.
Click the self-destruct button when you are in dire straits, and the only way out of there is to blow up the whole ship. Clicking the button will trigger a countdown:
Use the countdown fields to input the number of hours, minutes, and seconds before the ship's internal defense systems will detonate. When the timer reaches zero, the ship will blow up.
The "Auto" check-box sets the ship to automatically black-out all screens when the self-destruct countdown reaches zero.
The second box (yellow, listing 00:00:00 if Self-Destruct is not activated) will turn red and display the time to detonation when the Self-Destruct botton has been activated.