PA and Boss deleting emails at the same time leads to confusion

SBS 2011 server runs in London Office 1 with a VDSL Internet connection. The PA has access to the MD's mailbox through her Outlook 2007 profile from London Office 2, which has 10Mb leased line and VPN to Office 1. Every morning she deletes any useless emails not caught by anti-spam. She is a seasoned IT user and experienced in Outlook. This morning she deleted around 6 spam emails from the MD's Inbox using Ctrl and select but when she went to her Deleted items to permanently delete them she noticed an additional 10 valid emails in there from the MD's Inbox that she had definitely not selected to delete. They were fairly random so it's not as if she accidently deleted a single block. The MD has said that at the same time he was also deleting those same 6 spam emails from his Outlook 2007 profile in London Office 1. The simultaneous deletion of these emails shouldn't have caused this issue but can anyone suggest an alternative. The PA is very professional and would certainly own up if she wasn't sure and the emails were recovered so that's not an issue. Similarly the MD is very experienced and would say if he had done anything odd. Any suggestions?

Many thanks.