So, Ana said something interesting today, and I'm trying to work out what was going on

She was thinking about climbing up on a wall. Above the wall is a chain-link fence. Part of the fence was bent and pushing out onto the top of the wall, which would make it difficult to walk on that section of wall.

To explain why she wasn't climbing up there, she said "I can't, because of that's falling down" (emphasis mine).

Now - what does "that's" mean? Is it an accusative (can I say that in English? You know, most of what I know about grammar, which is already precious little, is in Latin... and a lot of that is wrong, WHICH IS WHY I AM CONFUSING ALL MY LITTLE DECLINING WORDS), like she'd say "because of him falling down"? (This seems most likely) Is it trying to be a possessive, is "falling down" some sort of quality you can own? (Probably not, but who knows?) Is it a mistake, one that everybody makes, where she was trying to run with "because of that" and "because that is" at the same time? (She didn't hesitate or stutter, so that seems slightly less likely.) Does she just not understand the rules governing "of"? (Doubtful - I'd've noticed before, wouldn't I?)

I've been thinking about this all day now, and I don't know any way to find out!