"Under a pyramid"?
There are some comments and questions to that:
1 The Egyptian government does not allow anyone to dig under the pyramids anymore. It was in the 19th century that such excavations could be undertaken without legal penalties.
2 IF you are permitted to dig a tunnel under a pyramid and put your razor blades there, you should think about the humidty level in such a location. It is true that the desert often is an extremely dry place, but keep in mind that there is a vertical RH gradient, which means that humidity goes up as you go down.
3 Is it really worth the trouble?
4 Should this posting be red-flagged?
5 Or, perhaps, red-stared?