In regard to your first video, that's sure a whole lot of covies in the second room! On my site there's a short article called
Massed enemy in the second room which mentions the idea of letting all the enemies collect, but I certainly don't recall the numbers looking
this striking, and I certainly wasn't aware of any infinite spawning dynamic. If there's indeed such a dynamic in the original H1, I'd sure like to know about it!
Can you say something more about what you're doing? Have you got a definite recipe by now? If you can give me a lead I'll get testing with PAL Xbox right away (I don't have MCC).