Coma patients are not 'living until their natural end' because modern medicine has developed so we can support them artificially. Perhaps it was God's will that they die, and we are interefering in this plan by treating them?
This point should be erased. The debate specifically says "Do you agree or disagree with euthanasia or mercy killing?". What is being advocated is the right of an individual to make a decision, not to have a say or coerce an individual to make the decision to want to die. Although in some cases, involuntary euthanasia has a dark region (grey area).