The first BOOM is the ugly sight of the nuclear shell striking its target, obliterating the psi-dominator, a few blocks of garrisoned buildings and a good chunk of Yuri's Black Guard.

After sending the prisoners running away, the second BOOM destroys the big gun's control, making the structure sag and almost fall apart completely.

By then Tanya is already leading the strike team down into the battle that rages and advances towards the Kremlin.