I think I bit off more than I can chew, in all the glory of ignorance, I uninstalled my microwave, flipped the internal recirculation fan to vent out outside horizontally. Now came the time to cut the 4X13 slot in the wall as the instructions advice. I slapped the template on there and went to town with the multi tool and cut 3 different boards, drywall, decolum and one other wooden board. Not sure what it is but it was thick and pressed wood. Now there was a small 2.65 in wide x 0.5 in thick wooden stud. But I decided to just cut it out and not re-strengthen the frame as it was a small wall framing stud and it wouldn't make much difference except making the task more complicated. Now, even while cutting the wooden board with my multi tool, noticed my blades were dulling out soon. When I removed the wooden cutouts I noticed there was no insulation and there was a freaking cement surface in there. I thought it was stucco, bought the 4 1/2 angle grinder with the masonry disc and started cutting and the blade doesn't seem to reach the end of the thickness, so used a SDS Plus masonry drill in my hammer drill to see how deep it was. The 5-in drill tapped out. So went out to home Depot and bought a 12 inch. And finally I was able to drill to the other side. DAMN that's a 10inch thick wall. I tried drilling few holes here and there with in the 4x12 space to see if it was all solid or were there any empty spaces....as usualy life hates me and it all 10in thick uniformly. What's the best and easiest way to buy this 10inch wall. The tools at my disposable are reciprocating saw or a hammer drill with separate hammer mode. What should I do now...banging my head over here.

Update: I gave up and paid a contractor 300$ to do the job. He bought a huge ass electric rotary gun and went to town on it...it was a very big tool.