1)
Why did they ask what to do to him? The lotteries showed that it is due to him. In any case they will throw him off!
1.
Malbim: They asked if he wants to repent and accept to go to Ninveh. This will be a solution for them ? they will return with him to the sore that leads to Ninveh. Or, they will return him to Eretz Yisrael.
2)
What is the meaning of "va'Yishtok"?
1.
Radak: The clamor of the waves will cease. This is like "v'Yismechu Ki Yishtoku" (Tehilim 107:30).
3)
Why does it say "Ki ha'Yam Holech v'So'er"?
1.
Radak: There is no hope that the sea will quiet down ? it is getting more stormy!