Honestly, there's no excuse for this, I think. You can easily go and get a cheap plastic tub from somewhere to house the other one in. They're competing for that spot, and yes it can lead to death. Separate them.
Ive done just as you instructed. I was told by people that I know with MUCH more experience than me that keeping them together would be fine, and that I was worrying way too much. It pisses me off that I didn't go with my gut on this one.