Modules (scribunto content model) do not allow a user to save the page if there are Lua errors. However, a user could change the content model to wikitext or something else, make an edit, and change it back to create a page with Lua errors. See https://en.wikipedia.beta.wmflabs.org/w/index.php?title=Wikipedia:TestTimedText&action=history
I don't know how blocking this issue is...
Note on above page: I created https://en.wikipedia.beta.wmflabs.org/wiki/Wikipedia:TestTimedText initially as a TimedText page, moved it to the Project (WP) space, and the Module space (where I changed the contentmodel to Scribunto), and moved it back to WP. https://en.wikipedia.beta.wmflabs.org/w/index.php?title=Wikipedia:TestTimedText&action=history
It appears that change to "Scribunto" is allowed only in the Module ns. I cannot change a Wikipedia page to "Scribunto", but a module page can be moved out of it to WP ns.