Isaac and Edward in “Unfinished Business”

[has just frozen a guard solid and boiled his comrade alive] Water freezes, water boils. Either way, you're just as dead. [A spear lands in front of him.] That's Alchemy...

Edward

What a nasty thing to do.

You of all people should know: Great deeds require great sacrifice. Isn't that the law of Equivalent Exchange?!

Edward

Save your breath. The laws of Alchemy don't justify murder!