I know from having flown the C310R, for the company in question, I know it preforms quite well on one engine.
As for doing the run up checks on the taxiway, well thats no different from doing them with the brake on, provided you do them correctly.
Pilot Pete, i need add no more to your post.
Gentlemen, there are loads of views, you all may have have carried out different actions, you all have different experience and skill levels, some of you may even have flown the type in question, but remember this, with the greatest respect, none of you where there.
Our thoughts must remain with the people who lost their life in this terrible accident.