Answer to
Q #1: Unfortunately you didn't give enough data about the X6 (model nomenclature)...because depending on which engine/transmission combo you have...you may be able to put the car in neutral using the tool (see
#1 in diagram below). But again, you may not have the tool depending on where your X6 falls in the production run:
Answer to
Q #2: How much do you know & understand about BMW's EWS (immobilizing) system? The vehicle will not start unless the key has the encrypted ISN individual serial number) that was coded into the key and other control modules off the assembly line. Only BMW has the database that has the encryption.