Typing the wrong number (large) by mistake is a kiss of death. There is no cancellation, so you have to kill MAX, and, of course, you better have saved recently. There should be some kind of 'Are you sure?"; this happens more often than you might think.
Thank you for reporting the issue when using the Connect tool. Freezing Max is the last thing users should encounter. It may lead to losing work in progress. We recommend using "auto-saving" in case something like this happens again. I was trying to reproduce the same issue, and yes, Max was working hard for two minutes to add 20,000 edges to the selected edges. Please allow a few minutes to complete the task.
