1)
Why did he say "ha'Dam ha'Anashim"?
1.
Rashi (Shmuel II, 23:17): This is said in astonishment. Metzudas David (ibid.) ? would I drink their blood?! Radak (ibid., 16) - since they risked their lives, the water is considered like their blood.
2)
What is the meaning of "b'Nafshosam Hevi'um"?
1.
'Rashi': They risked their lives for it.
