I'm really torn about this show since IMHO the finale with the Klingon war did not feel earned. L'Rell simply was not believable based on what we have seen. Hence a guess at a missing scene - Admiral Cornwell via holo-skype to L'Rell. L'Rell: Ah, my old captive, now in hiding. Admiral: Not hiding, planning. Listen carefully. Thanks to the Mirror Universe, we know how to destroy Q'onos. We can do it at any time. L'Rell: Nonsense, you (insult) wouldn't know a threat if it bit you in the neck. Admiral: This is our simulation of what will happen to the Klingon home world with only one hydro bomb. (Shows). L'Rell: Nonsense. Humans don't have the capacity for that level of destruction. We have tasted your blood-- Admiral: Humans invented a concept known as "Mutually Assured Destruction". We had this on our own planet between nations. It kept the peace. But know this - Starfleet will not fire first. However, if the Klingon fleet attacks Earth we will send dozens of ships including Discovery to Q'onos. They will all have these weapons. The Klingon homeworld will die. L'Rell: (shocked) You would not. Admiral: You have met the Terran. We are not that different. We have already planted one such bomb. As a gesture of good faith Mary Sue will give you the trigger. Use it to convince your people to stop the attack on my home. Or you can be assured of your destruction. (episode goes on).