do you think it's at all possible to shoot those 4 shots without thinking because you are 'irrational with terror' as someone said yesterday, and so did not even consider the obvious consequences?
No. I think he had the intention to kill, possibly because he was irrational with terror.
So rather than think 'I'll call for help' or 'I can threaten them with a gun' he went straight for killing them, possibly because this was the quickest way for him to get safe.
I don't think that he was so scared he temporarily forgot that he temporarily forgot what a gun would do.
I have previously thought that maybe he forgot that guns kill. There seems to be a dissonance between how he behaves around them, and the actual damage they can do. But having heard him speak, he's adamant that he was so scared he just wanted to be safe - to me, that speaks of an intention to kill.