Aah-Hmmm...,
If I may, may I stop this on-line panic mode about the steel cable (or other parts) breaking on the inside hood latch? Personally I have lost count on the hood latches -installed correctly- and later-now up to ten years later or more, I have never had one break....BUT-
If the system becomes unusable for any reason, go through the right vent! I assumed you/the builder used caulk to put the vent in place? Wiggle it loose, shove it to the inside and hey- you can reach the original hood box! You can take it apart through the vent-use a needle nosed vice grip-pair of pliers and pull the remaining cable to open....Cutting hoods to get open is NOT an option!
DV