(urth) PEACE: Typo or clue?

[Dave Tallman]

I'm continuing to look with suspicion on Miss Hadow, and I discovered 
what is either a typo or a significant clue. On p. 226 of the Berkeley 
paperback edition, she says "I'm Mr. Scrudder's secretary."  On page 
243, she says "...in Mr. Scudder's office I just come in and go out 
whenever I please." I read an Agatha Christie mystery where an apparent 
typo like this is a major clue. Does this same name error occur in all 
editions?

If this isn't a typo, she called her supposed boss by the wrong name. 
There is a Charlie Scudder, an executive vice-president (p. 135). Den 
drank with him in the early days of his presidency (p. 152).

Here are two possible explanations for the slip:

1) Hadow is an impostor. Weer says he doesn't recognize her (p. 226). 
Between his first meeting with her and the later one, she remembers (or 
looks up) the correct name. This would work if she is the Tilly ghost.

2) More interestingly, "Scrudder" could be a slip of the name she 
privately gives her boss. In the Urban Dictionary, "scrud" can mean "To 
harm, kill, or by omission of action cause to be harmed or killed, 
another living being."  Suppose Charlie was a fellow conspirator with 
Weer in the coldhouse prank, and Weer rewarded him with a 
vice-presidency when he inherited the company. If Hadow is related to 
the coldhouse victim, this may be her way of thinking of her boss as a 
killer. In this case, vengeance for this death may be her motive for 
killing Weer.

I suspect she poisoned Den's last drink. If she isn't a ghost, she can't 
have poisoned the first drink on p. 220. Miss Birkhead was at her desk 
when Den entered and nobody else came in until he called for Miss 
Birkhead and Miss Hadow came in instead. There was a bit of a delay, and 
Den had to ring twice (p. 226). Did Hadow kill Birkhead, or decoy her 
out of the way to get access to Den's office to poison him? 
Time-slippage makes the situation fuzzy, but I prefer to think of Weer's 
entries into the past as self-consistent where possible. It would 
explain the sudden secretary replacement without notice. She wrote 
Birkhead's death notice herself, so it need not be true (p. 243).

Why did she barge into the office when Den was meeting with Dan French 
with a trivial request that could have waited (p. 243)? She might have 
overheard on the intercom that French was having a drink with Den, and 
rushed in with the first excuse she could think of to save the innocent 
French if necessary. Something may have reassured her that French was in 
no danger. French was drinking whiskey on the rocks. Den at least 
sometimes drinks whiskey and ginger ale highballs (p. 152). Maybe the 
poison was in the ginger ale.

I realize this is a lot of speculation from a little typo. Does anyone 
agree this may be significant?