It's funny how it's those that aren't Christians are now telling Christians what their belief should be. Bonkers. It's interesting debate, but perhaps we should have it on a new thread.
Some Christians take the Bible very literally, some view it is very important but also take into account modern viewpoints, and on abortion and euthanasia the Bible isn't crystal clear. What he does emphasise is the sanctity of life, and that all life is God-given. There's obviously the commandment to not kill, but there's plenty of killing in the Bible, that God didn't seem to have a problem with, so even 'though shall not kill' isn't an absolute.
Respecting the sanctity of life means different things different to people. To me it means quality of life is important too. As is pragmatism. I believe that God gives life and God takes life away, however, that doesn't mean we should reject anything that could interfere with the natural course. Christians get treatment for cancer, have heart transplants, all things that you could argue are interfering with what does originally intended. So no, I don't have a problem with ending it early if suffering is intolerable and nothing can save the person's life.
The essence of being a Christian is not following a set of rules, but faith and personal relationship with Jesus. Generally, most people who have a faith in God will want to do what they believe will please him, hence, most Christians taking a lot of note of the Bible, but precisely how much an the interpretation of that is an individual thing. The key is your faith and relationship not following rules or good works.