That will only work if the character and walls are at least 30 pixels wide though — With a 2 pixel wall and a 10x10 pixel character it could skip right through. So you would have to considder the placement of every piece.. Here is your example but sizes are changed so it doesn't work anymore. https://dl.dropboxusercontent.com/u/1750576/gothroughwalls.capx
So this is really up to vorpalblade if it would work in his situation or not. Perhaps otherwise show as an example of what you mean vorpal..
Is there nothing like raytracing in construct? Anyone?
Otherwise perhaps use lerp and have an invisible object move from the character to the destination and report any overlay with solid objects which would cancel the move.
Not sure if this could be made practical and work but I know this would work in theory. Someone with proper Construct2 knowledge here that can give their thoughts on what I just suggested?