I'm pretty sure i saw that question somewhere, but i can't find it; what happens if yer dogboi gets wounded while in, let's say, 2' wide and 8' long lane between 2story building and the edge of the map? Is he backing up? Is he going up? Is he questioning his life choices? Or maybe he's not allowed to transmutate?
A 40mm base is going to fit into a two inch wide alley without any problems, but if it were an alley that was narrower than the new base size then the trooper would be Immobilized. See http://infinitythewiki.com/en/Models_and_Markers_Replacement
I'm still confused how i would handle that. Yeah the guy is immobilized but where do i put the immobilized trooper? He still transmutes right? And still does not fit in there. Do i keep the old S2 model in there?
Yes, but as a matter of practicality, the large model can't actually be there, the fact that the large model can't actually be there is the reason he has become immobilized. A practical solution would be "Use the smaller model, but treat him as filling as much of the larger silhouette as possible without clipping through walls". Nothing is going to be RAW though, RAW doesn't handle it.
Sorry, I wasn't clear enough. :-( In game terms, the new profile is what is locked in place in the narrow alley, but if there physically isn't enough room to place the new model then you'll need to place something to mark the position.
