means you pushed V/S or the ALT button
No, I pulled speed actually to maintain speed, as at it changed from SRS to CLB mode on its own (passing through the acceleration altitude)
does not accelerate out of its own on single engine
We had an engine fire and both engines were still producing power until I shut one down
Yes, I agree, looks like thats how to learn. By making mistakes in the sim and learning things which are not perhaps documented very well.
Like I believe somewhere in the FCOM it should say that "it will NOT engage the G/A mode if still in SRS mode after takeoff (if this is how it works)"