In Dr Strange, in the final battle, Strange and Mordo arrive at the Hong Kong Sanctum to it having been destroyed and the Dark Dimension leaking(?) in.
Strange immediately realizes the only weapon is the Time Stone and immediately uses it to reverse (global?) time and reverse back to before the destruction of the HK sanctum.
Kaecilius and the zealots managed to "warp themselves" out of the reversal and fight Strange and Mordo.
If that's the case, why wouldn't Dormammu be able to break out of that time loop himself?