Electricity on Shabbos is a big sugya that needs serious iyun, but here are a few potential points for clarification:
1. There is a difference between the D’Rabbonon of Amira L’Akum [also Muktzeh] and other Issurim D’Rabbonon enacted to avoid a D’Oraysa [which use of electricity may involve]. [The former is more lenient and more readily permitted for a Choleh She’ain Bo Sakanah. Amirah L’Amirah may be permitted in some circumstances where “two d’rabbonons” might not.]
2. A voice activated machine/computer has no connection to ‘mechamer’. An animal is a living being with a mind of its own. ‘Siri’ is a machine. “Talking” to Siri ?????? is no different than pushing a button or flipping a switch. [Using a machine mechanism in its intended manner isn’t a shinui.] ‘Akimas Sfasayim Maaseh’ is brought in Shas in a totally different context WRT chiyuv Misah/Chatas/Malkos for Issurim involving speech only.
3. Using a “Shabbos elevator” is a sugya unto itself, and not at all poshut. However an ‘automatic driving’ car is even more problematic. The user of a “Shabbos elevator” has no input in the timing or route selection of the elevator. The user of the Tesla, even if he chose the route before Shabbos, would still be choosing on Shabbos when to depart, and thereby activating the system. The weight of the passengers also influences the actuation of the motor and activates sensors even more so than in an elevator.
4. It also isn’t poshut that NO D’Oraysa issurim are involved in operating a Tesla. Any parts of the motor heating past a certain temperature may create an issur D’Oraysa, among other possible issues.
5. Even without actual ????? ???, the iron mistakenly left on was subject to the Heter of ????? ???? ?? ???? – quenching a red hot piece of metal (issur d’rabbonon, as opposed to a burning charcoal which is d’oraysa) left where people could be hurt by it, which is permitted. By doing even one of the shinuyim used, it would be muttar even according to the Poskim who hold it is d’oraysa.
6. If and when an electric ambulance would be technically possible, it would definitely be preferable to a gas driven ambulance.
7. For a paramedic/doctor/Hatzoloh volunteer driving their own vehicles, or a husband taking his wife to give birth, an electric car would involve much less Chilul Shabbos. In a ????? ??? scenario, if you don’t have immediate access to an electric car, it would be assur to delay responding in order to find one.