Silly pilot.
Not much chance of someone getting hurt but a good chance the trouble shooting results from the test will be compromised.
That switch is selected prior to almost all BITE System tests. It allows systems to operate during tests that would normally be inhibited. EG CAC/Pack with only two Ground Electrical Power sources.
If the engineers are working on the aircraft please ask before touching anything. We're just trying to do our job as quickly as possible, the aircraft will be ready when it's ready, not before.