If I recall correctly a American Airlines 727 crashed shortly after takeoff on night, west bound out of LAX, when the FE left the APU running and essential power on the APU and when he realized what he had done he shut down the APU with the Fire Shut off switch causing the loss of all flight instruments.
In actual fact (circa 1969 or thereabouts) it was a UAL 727 that went into the drink just off LAX...nothing to do with the APU, it was the misinformed Flight Engineer that switched OFF the ships battery switch, after having all generators trip offline, due to a differential fault (dispatched with one generator inop).
I know because I helped look for/find the wreckage.
Not a happy night...
Be aware...in too big a hurry sometimes makes the problem/situation worse, and results in bypassing the hospital altogether, and proceeding directly to the cemetary.
As in...dead as a doornail.