I don't think he said he's willing to die. He said he's willing to test it, and presumably he'll continue concentrating and will manually take over if the car does something dangerous.
He came fairly close, honestly. "I'm going to do my best not to die, but I'm excited about this tech" is recognizing, and accepting that death is a possibility as a result of Tesla's self driving process.
There's risk of dying every time I get behind the wheel of any car. There's no benefit to pretending real risk doesn't exist in any given scenario. I'm confident that I can be attentive and cautious enough using this tech to keep the risk similar to what it would be just driving normally.
That's assuming he's always able to intervene before it kills him. The argument is that he may not always be able to or prevent AP from behaving erratically enough that results in killing someone else (while he saves his own life).