The most critical task should be to cooperate with Lord Qin himself to ambush the Crown Prince and Prince Qi, ensuring that these two must die. Otherwise, even if they control Emperor Gaozu of Liang, and the Changlin Army from the Crown Prince Mansion arrives, the situation would still be precarious.
Controlling Emperor Gaozu of Liang, on the other hand, was the second most important task.
The difficulty of this task was actually lower than ambushing the Crown Prince and Prince Qi, since the Crown Prince and Prince Qi were always on alert and had many private soldiers, whereas Emperor Gaozu of Liang had never imagined that his own sons would target him, hence was caught off guard.
Moreover, the majority of the manpower from Lord Qin Mansion was used to eliminate the imperial guards and take control of Emperor Gaozu of Liang.
