When that closes, Firefox will be open and state that it has been refreshed. In order to completely remove Critical Error! Tech Support Scam you will need to reset Safari back to its initial settings.

Microsoft Security Essentials detected potential threats that might compromise your private or damage your computer. Your access to these items may be suspended until you take an action. Click 'show ...

The vacuum seems fine, but in HA it shows an exclamation mark beside it, and in its attribute theres "Error: Remove mop". No mention of this inside the Mi Home app.