The situation in Atlas is dire.
What he's feared for so long has come to pass at last. Salem's forces have descended upon Atlas and Mantle, attacking soldiers and civilians alike. Their dust supply is extremely limited and threatened. The city of Atlas has sustained severe damage all across its streets, some in crucial areas. And the Winter Maiden has gone rogue.
But all hope is not lost.
Although some of the hunters and huntresses that are supposed to being doing their duties and protecting Atlas have defected, he still has the Ace Ops (what's left of them, anyway). He still has his army, his tanks and drones. He has Arthur Watts detained. And the Winter Maiden is still well within his grasp.
He just has to find her.
The Winter Maiden is the key to fixing Atlas' current problems. His soldiers can eliminate the Grimm attacking the city, the Ace Ops can destroy Salem's stronghold and hopefully weaken her in the process (he's not foolish enough to expect the bomb to outright kill her), but only the Winter Maiden can allow him to access the staff that will allow him to raise Atlas to safety.
The Staff of Creation.
Once the Winter Maiden has been captured and brought to him, he can take her to the vault and have her open so he can retrieve the staff. Once the staff is in his possession and his forces have cleared Salem's remaining forces in Atlas, he can use the Staff of Creation to raise Atlas high into the atmosphere, well out of Salem's reach.
Regrettably, the people of Mantle will not be able to accompany them. It's unfortunate, but a necessary sacrifice under the circumstances. They are in a time of war, after all.
And keeping Atlas out of Salem's reach won't just protect the people of Atlas. By keeping the Winter Maiden and Staff of Creation out of her grasp, he'll be preventing Salem from achieving her ultimate goal of uniting the four Relics and destroying the planet. He's looking out for everyone in Remnant, not just his kingdom.
Although Mantle is likely to be overrun before long, well before any kind of help can arrive, Vacuo and Haven are unlikely to suffer the same fate. Although Ruby Rose and her friends had gone against his orders to issue their broadcast across Remnant, some good had come out of their actions (despite large portions of their message being inflammatory and patently untrue). The rest of the world knows about the danger they're facing. They'll have time to prepare.
But for now, he must prioritize Atlas. The time has come to do what must be done.
He contacts Winter. "Mission status?" he asks without preamble.
"Everything is currently in position, sir," she replies promptly. "We have the charges set to detonate as soon as we're certain that the site has been cleared."
"Make sure you don't wait too long," he reminds her. "Don't hesitate to take your shot while you're in a good position. We don't want this opportunity slipping away because we were too cautious."
"Yes, sir."
"And once you're finished there, I want you and the rest of the Ace Ops to head back here immediately. Leave the cleanup to the rest of the soldiers. We have urgent matters to attend to."
"Yes, sir."
He ends the call with Winter and stares down at his desk as he carefully considers his plan. One way or another, he will have the Winter Maiden returned to where she belongs, in Atlas.
It's the only way out of the situation.