I'm away from the house but I have my .scriv file on cloud storage.
My question is, can I get to a particular chapter in my story and make some quick edits? Will changing these files break the program when I launch it next?
Are you using scrivener on another computer to edit it? If so, you shouldn't have any issues, just make sure you save, and let your cloud platform fully sync before you go to work on your main computer again.
If you're not using scrivener, make a backup of the file before you try!
I work on my Scrivener files outside of Scrivener (using Vim and Multimarkdown Composer) more than I do inside.
To do so, set Scrivener to sync your project using external files (File > Sync > with External Folder) to a folder in Dropbox (or whatever syncing service you are using). I recommend setting Scrivener to automatically sync on opening and closing a project, which is an option available in the dialog when you are setting it up.
Then your Scrivener documents will all be stored as individual files that you can edit at will with whatever editor suits your fancy on whatever computer/device has access to your synced files. When you open the project, Scrivener will check and sync that folder to bring in your edits. If you add new documents to that folder, Scrivener detects them on the next sync and verifies you want to bring them into the project. They end up in your research folder until you put them in the proper place.
I work primarily in Markdown, but it works fine with RTF files and RTF capable editors as well.
This is a significantly safer alternative than opening .scriv files on multiple computers.