If no one actually saw me in the courtyard, I'll eat my cloak. Every window in the ballroom faces that way; you'd have to be purposefully staring at your plate for an hour to not notice.
I would suggest that a fifteen minute gap is sufficient. No one would notice if, for example, Bernkastel or Miss Carter left lunch 5 minutes earlier than they said. 12:55 is the same as 1:00 in most people's minds; 12:40 close enough to 12:45. No one would be able to vouch for the time that precisely.
If you think the time period is tight, I would ask you what else the murderer would do following the crime. It would be stranger if they dawdled for ten minutes before appearing in the place they want to establish an alibi.
no subject
I would suggest that a fifteen minute gap is sufficient. No one would notice if, for example, Bernkastel or Miss Carter left lunch 5 minutes earlier than they said. 12:55 is the same as 1:00 in most people's minds; 12:40 close enough to 12:45. No one would be able to vouch for the time that precisely.
If you think the time period is tight, I would ask you what else the murderer would do following the crime. It would be stranger if they dawdled for ten minutes before appearing in the place they want to establish an alibi.