You can boot to it without doing anything more than getting to the initial screens.   You could even select the repair option on the second window and it will not do anything until you allow it.

If you were to make a mistake and select to install, you should be able to cancel prior to creating any partitions or designating install locations.

The bottom line, if it boots to the first window it should work fine and you can terminate that process then.

Thanks.

Mark