In my opinion, tab character will not be the only issue: I don't see how you might be able to use proper continued numbering with this pattern.
May I suggest converting your text into a table? So you can easily apply continued numbering lists along with proper alignment...
@Colin – Give it a try with using several paragraphs on one line by setting their leading to zero.
In that scenario you'll need at least one character in every (empty) paragraph so that the numbering could kick in. Use a zero width one for that.
That's cheating! But it does work. It fulfils the brief, but I'd hate to see what would happen when someone else opened the same file and tried to work out what on earth was going on... because even in story editor it's hard to see what's going on unless one looks at the para formatting on the left hand side.
Your solution is good too, but Laubender's solution allows the type to stay in the text frame without having to mess around with formatting tables, especially as there are images that may need to wrap around the text and this can be problematic in table cells - i have documented this before - A fable of an unstable table | Colecandoo! (heading 3 of the article).