what happens if I remove my apple watch from its cradle during an update? It was an accident.

Hi

Apple Watch should not be removed from the charger until the software update has completed.

If your Apple Watch is now displaying a red exclamation mark, then you will need to contact Apple Support, make a Genius Bar reservation or visit an Apple Authorised Service Provider to arrange for your watch to be serviced:

• Contact - Official Apple Support
• https://twitter.com/applesupport
• http://www.apple.com/retail/geniusbar/
• https://locate.apple.com/

More information:

Get help if your Apple Watch displays a red "!" - Apple Support

As long as the battery doesn't die during the update, your Apple Watch will be fine.