Fair enough, I'll give the shape of that some more thought as we continue further and I start to understand Alexi a little better. 

He literally will never say that he's ready to take it and mean it. Keep that in mind. He truly does believe he'll die first. Buuut, he might say he's ready just to try and draw Alexi close enough to get a few drops directly from his body. The fact that even if he succeeded, he would only be prolonging his own suffering, hasn't crossed his mind enough for him to care. He is basically acting on two instincts, the need for blood, and the knowledge that he cannot get it from the potion.