Just finished reading this. It's the first ever Aliens comic that was laugh out loud funny. I knew people would lose their marbles over the grenade, and it is a goof up. No question. It could have easily been fixed as there was no shortage of explosions rocking the atmosphere processor leading up to the explosion. Alas, it is what it is.
What most people are missing here is that Burke is a narcissistic psychopath. They are characterized by not being able to distinguish right from wrong. They can't tell when they did something wrong, and they don't understand why someone is upset at their actions. Did them it's just a "bad call". Oops.
They absolutely nailed the psycho-pathos which characterizes Burke quite well. He is capable of sweetness, and tenderness and completely oblivious to the evil he does. I think we all know people like that and not all of them are killers. But if they were, they wouldn't carry any guilt around.
Great fun story if you overlook some continuity errors.