[quote=knighthawk]
So what happens when a regenerating mutant is fused into a brick wall?
[/quote]

Well they suffocate they have no air around them but simply a brick inside there body. 
The phasing ability lets kitty too go through walls with there molocules like..I can't explain
damn science but if a regenerating mutant was stuck inside they'd just stay there XD
normals would suffocate and other non-regenerating mutants.