Away from the Ivanov chaos, the siblings still needed to deal with Amelia and her ability to get herself in danger more times than anyone could ever deal with. This was because if she was going to be putting herself in danger all the time then they had to find a way to keep in check.
She was the very reason they had invested their time in all of this.
They didn't want her to do it alone but they also didn't want to sit on the sidelines as her royal highness put herself in danger once again.
Their sister was stubborn. But she had her reasons.
They would help her help them, and when this was all over they would swear to never take on a mission again, coz they needed to lead normal lives. They needed to create families on their own. They needed to return the love they were getting form the people who cared about them.