The man page for whiptail says that you can "move between the menu entries by pressing the UP/DOWN keys, the first letter of the tag as a hot-key.". So if you press the r key twice and then hit enter you will get a root shell.
To make this more obvious you could change the menu entries to something like "(R)oot Drop to root shell prompt" or "2 Drop to root shell prompt".
The man page for whiptail says that you can "move between the menu entries by pressing the UP/DOWN keys, the first letter of the tag as a hot-key.". So if you press the r key twice and then hit enter you will get a root shell.
To make this more obvious you could change the menu entries to something like "(R)oot Drop to root shell prompt" or "2 Drop to root shell prompt".