Virtually all cars, all MGs included, have the traditional mechanical brakes and duplicated hydraulic system, operated by the brake pedal as well as by the emergency braking computer (if enabled). At worst, if the vacuum pump fails (the vacuum hose in an ICE could fail too, or the engine could stall), you may have to apply stronger pressure to the brake pedal than usual ("stand on the brakes"), but it still stops safely.
So EVs are absolutely no less safe with braking, and most have yet another way to slow the car, regen via the motor. I suppose you could use the clutch on a manual ICE with a stalled engine and failed brakes to slow the car in a somewhat controlled manner. And of course all cars have a relatively weak (compared to the foot brakes) parking brake, whether hand operated or electrical.
The scary thing to me is the steer by wire that Tesla are introducing starting with the Cyber Truck. That has no traditional steering wheel shaft, only electrical connections to the computers and motors that drive the steering rack. How they got that past regulations, and get it to be safe even when the truck is 20 years old and the batteries are clapped out, I have no idea.