1)
Why did they scream?
1.
Malbim: Perhaps it is sleeping.
2.
Perhaps they screamed, for they suspected that Chi'el is not making the fire (refer to 18:26:5:1) because he is sleeping, or the Mizbe'ach blocks their voices and he does not hear them. (PF)
2)
What is "Yisgodedu"?
1.
Rashi: They scratched themselves with a Kli.
3)
Why did they scratch themselves?
1.
Malbim: Perhaps it will feel the pain of its Nevi'im.
4)
Why does it say "k'Mishpatam"?