Shooting people runs a high risk of killing them, end of story.
The PC pulled out the blaster, aimed it at another person, and pulled the trigger. If the player wanted to stun or wound the NPC, he should have said so as part of his statement of intent, up front. But he didn't, he just attacked him with his blaster.
The PC killed the NPC.
A player having their character whip out a blaster and shoot someone, with no stated qualifiers, is leaving the result up to the random hand of the dice -- and expecting the GM to bail them out "because narrative" is weak.
Edited by MaxKilljoy