I think Draco is very interesting character. All his live he has looked up to his father as his idol and wanted to become like him (just read - become Death Eater), to make Lucius feel proud about his son... So.. Draco goes and takes th Mark just like Lucius son should do... BUT..!
When Draco feels what it realy means to be death eater he understand that it isn't what he thought it will be...

Draco stays alive. Well, he could die...but he will be on Orders side.