It’s possible with ‘ure_supress_administrators_protection’ filter (return true for it) to make users with ‘administrator’ role visible to user who can edit users, but such user will can edit “admin users” then. URE does not offer ‘read-only’ mode for users page.
So after you switched off a default URE protection for users with ‘administrator’ role you have to:
1) use ‘map_meta_cap’ filter to block editing users with ‘administrator’ role;
2) exclude ‘administrator’ role from WordPress dropdown lists in order to prevent creation of new administrators by yor Editors: ‘editable_roles’ filter.