How Phplist handles sending emails if computer is turned off suddenly during sending batch emails

I want to know if computer is shut down during sending batch emails, what happens to sending emails process? If I start my computer again and process queue, does phplist resume sending batch emails or start from the first email?
I didn’t set cron job and when I send test message, phplist said Leave the Window OPEN.
By the way, is it possible to send message to batch emails and shut down the computer during the sending process WITHOUT SETTING CRON JOB? I want to send message to 125000 emails.

Each email is flagged as sent at the time it is sent so there is no danger of resending multiple emails.

The choices for processing the send queue are to either leave your computer open or to set up a cron job.