Reformat hard drive - why do I have two hard drive options? I'm trying to erase my hard drive by reformatting. I am following the steps here:

https://support.apple.com/en-us/HT204904 

I am using the  Opt ⌥   Cmd ⌘   R   option on startup to install the latest OS compatible with my device. When I get to the erase screen, I see the following hard drive items listed:



This is different than what the directions are showing. Should I be erasing both "Macintosh HD" and "disk1"? I've never made any changes to my hard drive, it's a MacBook Pro 2014. Not sure why there are two entries there.
'disk1' is a temporary structure &amp; the 'disk' you are currently booted from, generated by the image you downloaded from Apple as part of Internet Recovery.
It will disappear as soon as you boot regularly from your HD.

That's how you are able to format your main 'Macintosh HD' drive, which you cannot do from the drive you are booted from.  

You can verify this since the system won’t let you erase disk1 even if you attempt that operation - that’s a snake eating its own tail situation.