It was not clear whether Mr Verloc had in his mind Spain or South America; but at any rate somewhere abroad.
This last word, falling into Mrs Verloc's ear, produced a definite impression.

This man was talking of going abroad.

The impression was completely disconnected; and such is the force of mental habit that Mrs Verloc at once and automatically asked herself: "And what of Stevie ?" It was a sort of forgetfulness; but instantly she became aware that there was no longer any occasion for anxiety on that score.

There would never be any occasion any more.

The poor boy had been taken out and killed.
The poor boy was dead.
This shaking piece of forgetfulness stimulated Mrs Verloc's intelligence.
She began to perceive certain consequences which would have surprised Mr Verloc.