Your understanding of the sentence is correct. I'm not sure which part of you mean specifically though.
means 'killing' as you have pointed out. , means "not," which I'm sure I don't need to tell you. is an abbreviation for in this sentence. means something like, "It seems" or "I'm sure," among other things (take your pick here).
is used here because it is preceded by the nai stem (). According to goo dictionary it means to "emphasize" or "make sure."