Just seen the footage regarding the number 1 engine.
Engine control experts, have you ever seen a water ingestion test for certification? You are better off with a bit of rag to throw in the intake. If the FMV fails the first thing I reach for is the lp valve p/b or fire p/b that is an aircraft system to shut off the source at the tank.
The fire truck is definitely spraying water not foam, I doubt qantas would want a double engine change!
The video is a bit grainy but that engine is below gnd idle. Got to love a bit of speculation, maybe a bit of oppertunity maintenance for a compressor wash.