If anyone else encounters this particular “status: 1” error (I know a number of people have received this, but it seems for different reasons)… I can confirm depa’s comment and will add to it to create an answer to the question:
I just had to install Homebrew myself using the command from brew.sh:
ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)"
Then when I ran the RVM install command again it worked fine.
It seems RVM had a problem installing Homebrew on my machine for some reason.