Possible idiomatic reference to the site of Christ's crucifixion in the Bible.
Compare with "... the great city, which spiritually is called Sodom and Egypt, where also our Lord was crucified." (Revelation 11:8), "And they bring him unto the place Golgotha, which is, being interpreted, The place of a skull." (Mark 15:22)
Eunuch: "What's going on over there?"
Leper: "They're leading Jesus all the way out to Bumfuck, Egypt to be crucified, hanged, whatever..."
A term used to describe any middle-of-nowhere, backwoods area, particularly one that is a long distance away. Derived from bumfuck, also used to describe a similar location. The addition of "egypt" originated in the Midwest, describing the "Little Egypt" region of Illinois, an extremely rural area compared to the urban Northern Illinois. See also BFE.
We had to drive all the way out to bum fuck egypt to pick her up.
The most remote, awful, backward, filthy, hostile place or town anyone can imagine; a location just this side of hell.
When they ran out of gas 50 miles from nowhere, one of the traveling guys exclaimed "My God, this place looks like "Bumfuk Egypt", there's nothing here but dead people and dog shit!"