Lots of conflicts need to be made real. Which mean you have to make the danger real. And how better than to show it killing someone? (Even if you don't agree with G. K. Chesterton's position.)
Preferably, alas, someone with a name, and with a background, and with the audience's sympathy. Of which the last is most vital if you really want to raise the tension level and create an impression of real danger. The fun part is making the character sympathetic to yourself as you are writing, and then doing terrible, terrible, terrible things to him. Even inventing someone to die doesn't fix the problem.