"No, no- justice will not allow you to say that. You didn't wan to. I didn't work with you." (616-617)
"I did it- I admit it, and she'll back me up. So I bear the guilt as well." (614-615)
"Hades and the dead can say who did it- I don't love a friend whose love is only words." (620-621)
"But now you're in trouble, I'm not ashamed of suffering, too, as your companion." (618-619)
"Don't try to share my death or make a claim to actions which you did not do. I'll die- and that will be enough." (624-626)
"But if you're gone, what is there in life for me to love?" (627-628)
Ismene told Creon that she was the one that buried Polyneices, when it was actually Antigone that buried him.
"Ask Creon. He's the one you care about." (628)
"If I am mocking you, it pains me, too." (630)
"Even now is there some way I can help you?" (631)
"Why hurt me like this? It doesn't help you." (629)
Antigone is trying to tell Ismene that even that even the gods know she buried her brother, so Ismene has no way to prove it was her.
"Save yourself. I won't envy your escape." (632)
"I feel so wretched leaving you to die." (633)
Antigone is trying to tell Ismene that when she dies she have to worry about her. She wants her to know that it's her fault for her actions. Ismene is worried that there will be no point to her life if Antigone is gone.
"But you chose life- it was my choice to die." (634)
"But not before I'd said those words just now." (635)
Antigone tells Ismene that since she didn't want to help bury Polyneices because of the consequences, that she should ask Creon what she has to love in life.
Antigone knows that the best thing for Ismene is to forget about her getting put to death because of her crime. Ismene feels bad knowing she can't do anything to try and help her get out of death.
It was Antigone's idea to bury her brother and she knew the consequences that came with it, but she wanted to do it anyways to give him a proper burial.