Now Inglethorp's out of the way, there's no one else; no one, I mean, except ”one of us." Yes, indeed, that was nightmare enough for any man! 
It would have been so much more convenient for everyone if Inglethorp had been guilty. 
mnli hypothesis: It would have been so much more convenient for everyone if Inglethorp had been guilty.  premise: Now Inglethorp's out of the way, there's no one else; no one, I mean, except ”one of us." Yes, indeed, that was nightmare enough for any man! 