There were numerous problems with his plan. First, there were no holes in the clouds. Plus, if he did manage to get on top of the clouds, the risk of spatial disorientation was very high at night over the clouds and the mountains. Moreover, the minimum IFR altitude over the mountains is 9,000 feet. That would also be the minimum safe altitude VFR at night. It is very likely that the heavy 172 could not have made that altitude under the given conditions. Finally, if the pilot did make it over the mountains, the updrafts and downdrafts very likely could have resulted in loss of control.