I'd like to have 2 extra packages of water and firewood.
I see. And I would like 2 extra packages of Food and 2 packages of  Water as well.
I have a great risk of dehydration.  I really need those 2 extra packages of water. You can have all the extra food.
Why do you have a risk of dehyrdation? Because I believe all people do but I do understand some people are at a greater risk then others. Tell me why you are at risk?
I have a medical condition that requires medication, and this medication requires me to drink an extra amount of water or else I will dehydrate. 
That is a problem. Does the medication require the use of fire or firewood as well?
No, of course not. You can have the extra of those if you'd like. It is really the water that is the most important to me. 
Hmmm... I don't really need the firewood,just the food which you are offering and the water. 
Okay, can I have the 2 waters and 2 firewood then? I will give you all of the food, and 1 of the water. Do you need any firewood at all?
Since carrying the extra would could make your dehydration worse, I'll take any firewood you don't want. But I'll give you the 2 waters and firewood then for the 3 food and 1 firewood. Deal?
Yes,thank you for agreeing to the water. I'll give you all the food (3) and 1 firewood and 1 water 
I couldn't live well with myself if I would let you die. You can have the two waters and 2 firewoods. Please be careful with your meds.