MM knows all along what happened in Pilkhana and took full advantage of the situation by reading the mind/psychology of Hasina and pushed Rohingya. You see, Hasina is a big talker but little doer.
Now, MM has shown St. Martin in its map. Something will happen in the future and do not expect Hazrat Hasina will act. She just wants to be in power.
It's quite obvious Myanmar is preparing for a war with Bangladesh. Consider their recent purchases like SY 400; ballistic missiles are outright offensive weapons. There are few factors which would influence their plan on going for a war.
1. How their internal peace process with the rebels pans out.
2. The state of the popularity of military leaders within the country.
If the peace process falls apart or if the military leaders began to lose their popularity based on economic or other conditions of the country, it's highly likely that Myanmar will go for a war against Bangladesh to divert the attention.