A colleague was tinkering with grep and, thanks to him, I discovered a bit more about the trusty little utility.
I had not really explored the -e switch: -
-e pattern, --regexp=pattern
Specify a pattern used during the search of the input: an input line is selected if it matches any of the specified patterns. This option is
most useful when multiple -e options are used to specify multiple patterns, or when a pattern begins with a dash (‘-’).