My brain can "switch mode" when on a regular web page, but if I open some kind of "terminal in a page" (i.e. I the AWS console), then I'm 100% it will end up with a C-W.
It's right near Ctrl+Q, which usually quits an application.
While Q is mnemonic, W is not.
It's too ergonomic and requires very little wrist movement for such a destructive action.
I understand your pain, but I blame the author of this weird convention for the "close tab" action, whoever they are
I've lost countless SessionManager terminal sessions this way on Windows and Linux.