Hi conner4545,
We understand you have questions about using fall detection. We're happy to help.
You are absolutely correct, if your iPhone is powered off or not in range you can connect your Apple Watch to a Wi-Fi network so all of the features will still work.
Connect your Apple Watch to Wi-Fi
If you trigger fall detection and the watch does not have a cellular or Wi-Fi connection, you will see the fall detection notice on the screen however, it will be unable to make a call since there is no network connection. You can find more information on fall detection here: Use fall detection with Apple Watch
You can also find more information on the things that will work when your paired iPhone is not in range here: Use your Apple Watch without your iPhone nearby
We hope this helps. Take care!