If we must die, let it not be like hogs (1)
It doesn't matter how nicely you treat livestock, they do not die honorably.
Making their mock at our accursed lot. (4)
This is an insult to the speaker's honor.
If we must die, O let us nobly die, (5)
The speaker knows he's going to die, but wants to have control over the way he meets death. He chooses an "honorable" death instead of showing fear or trying to escape.