When something fails during testing, or you have to shut something off because it’s dangerous, contact your clients real estate agent (or the listing agent if the clients agent is not available) and advise them of the situation and what they need to take corrective action and put it in your inspection report.
You are responsible for things like dropping the ladder you’re carrying through the house on the TV. You’re not responsible for operating what your client would normally operate and subsequently have it break during testing.
You are there to do exactly what caused the failure (running the dishwasher). It’s the sellers responsibility as well as the listing agent to notify you (and your client) of anything in the house that is taken out of service, is dysfunctional or is a safety concern.
Crap happens sometimes and no one is responsible.
As for dishwashers, if they are simply not properly secured to the base cabinet and they tilt out, I will not operate them because they are not properly installed.
Inspect the installation of the components you are about to test and if they are not properly installed, don’t do anything else!
If you have an overheated circuit breaker, you don’t turn on everything on the circuit to “see what happens” do you?