Nitpicking, I know, but releasing 400 volts means nothing. Current kills, tension does not. It all hinges on the internal resistance of the power source.
400V can overcome your body's resistance no problem. And obviously an EV has a crap ton of amperage as well.
However, there is definitely a risk here, albeit what appears to be a manageable one. Perhaps there could be some use in building volt meters that glow into gloves for emergency responders to help mitigate some of the risk.