Does your username have sudo ability?
Edit: - I see you do have sudo.
I have never seen the script exit silently, maybe @dceejay might know what's going on.
If I had this problem, here's what I would do as an experiment. Never tried this.
1 Download the script curl -sL https://raw.githubusercontent.com/node-red/linux-installers/master/deb/update-nodejs-and-nodered > nrinstall
2 Edit the script to remove the code which throws away output sed -i 's|>>/dev/null||' nrinstall > test
3 Run the edited script bash ./test
If you are lucky there will be an error message, or possibly lots and lots of output.
