hoping this works.
-information stage, split into taking, using and giving information (e.g. seeing a junction with other traffic, deciding where you're going and then giving a signal). here you gave information in that you revved your engine. Using the horn would have been ideal although you could justify this by saying the horn is quite pathetic and the exhaust note is louder when revved than the horn. This is the beginning stage and runs throughout the whole thing. It includes things such as considering road surface conditions, taking in mirrors, other traffic, upcoming hazards, etc.
-position - considering position on the road for maximum visibility (seeing and being seen - make sure you make clear you were easy to see, if you were wearing any high vis or bright colours, make this clear - hivis can make a big difference to perception of how incompetent someone has been), best navigation of the hazards, etc.
-speed - adjust your speed appropriately for the hazards, surface, weather conditions, surrounding wankers in tin boxes, etc.
-gear - select the correct gear to ensure you have maximum flexibility in terms of engine braking and acceleration if required. Also, if you were in first gear you can say this was chosen in order to make as much noise as possible.
-consider lifesaver (irrelevant here, really)
-acceleration -accelerate smoothly back up to road speed, again probably not relevant here.
The difficult thing is that if you see a car in that position when you're filtering, you're best off stopping and ensuring they've seen you or letting them finish pulling out. You may take some blame here.
I do take exception to filtering being a hazardous activity - cyclists filter all the time. It's the point of riding a bike. Adequate observation from idiots in boxes means filtering shouldn't be an issue.
I hope my slightly drunk, definitely high ramblings help.