1)
Why did they scream loudly?
1.
Malbim: Mo'av was already broken.
2)
What are "Tze'ireha"?
1.
Targum Yonasan: Its authorities. Rashi - these are the young kings. Radak - perhaps its great leaders are called "Tze'ireha" for disgrace.
2.
Malbim: They are the people of Tzo'ar, to which the refugees fled.
