You can do it in the garage, but your battery has to be fully charged and I'd recommend it being on the battery tender when you do it. Andrews car had a very unlikely incident, but it is possible an update could screw up your computer making it impossible to do anything with the car. The rear parking brake is engaged which makes it hard to get it on a flatbed if the car won't power up.
Updates download one at a time in the order they were intended and will only do one at a time. They will also not come in one after the other in rapid succession, but rather spaced weeks or months apart. Even then if it fails or it's refused, it may take weeks to download it again. It's usually many months between updates anyway.
Remember that updates are pushed and can not be pulled, so you will likely not get an update for several weeks depending on how the car is stored. If stored on a tender it may very well have an update pushed to it.
Don't be confused with the "Check for updates" you see in the menu. That is for Android auto or Apple carplay apps (etc.)