Dania's complexion changed because she suddenly thought of a possibility.
If the demonstration she orchestrated turned out to be very successful and effective, leaving Mikhail in a state of disarray and severely damaging his reputation.
Of course, such harm for Mikhail could only be considered "superficial wounds" at best and could possibly cause some potential problems in the future, but it wouldn't be enough to cripple him immediately.
What could she gain from it?
Setting aside whether the promised benefits could be fulfilled, what if the other party was ruthless enough to want to extend their "victory" and simply kill her off!
This scenario wasn't improbable at all, but quite likely!
In a place like Moscow, the death of an insignificant, unknown lawyer wouldn't count for much.
Moreover, eliminating her would be greatly beneficial for the Moscow faction, which could be seen as "small investment with quick benefits."