So, how many people can Luke expect to kill him if he dies?

Depending on who else dies, he may escape by coming second or third on her list.

FOr Pepper.

What is he more afraid of: Getting killed by INara or the look on Kaylee's face?

She won't be mad, she'll be SAD, isn't that worse?

... Wes may be a bro and point out how much trouble he'll be in

Oh boy. Well, Luke's died a couple times before and the actual dying wasn't that bad. Probably Kaylee's face. It'll tear him apart but he'll just have to deal because people are in danger.

He has to be the hero.

I'll have to check if there's something in the bro code about preventing people from charging into a situation taht will get them in trouble