I can't seem to get a straight answer anywhere, so does anyone here have advice/experience with leaky basements?

So here's the story...

I live on the main floor of a house with two units. I also am the only one who has access to the house's unfinished basement. A couple of weeks ago, I started hearing loud banging off and on when the plumbing was used. I thought nothing of it, until last week, when I took a peek down in the basement and saw water pooling on the west end of it. Upon further examination, water seemed to be coming down in a small deluge whenever the upstairs tenant would use the plumbing.

As of now, the west side of the basement (where the pipe is) has at least an inch-thick layer of water along the floor, tapering off somewhere around the middle. I've also noticed a bit of water on the east side, which is where the house's sump pump is located.

I've contacted my landlord, who directed me to make an appointment and get it addressed, but they won't be able to come out until next Wednesday. Meanwhile, while the flooding doesn't seem to be getting dramatically worse, it's still fairly constant and I have a few concerns that I'm hoping someone here can shed some light on.

• I noticed that the pooling water is approaching my gas furnace - should I be concerned about that? As I said, the water is maybe an inch deep, and doesn't seem consistent enough to rise above that level. Googling has told me that flooding of any kind near the furnace can result in fire and/or explosion. I contacted Enbridge's emergency line (as their site tells you to do in case of flooding), but they basically blew me off.

• Due to the water build-up, the house is starting to get a rather musty smell, which I'm assuming is mold. There are resources all over the internet about mold, but they all seem to say something different about when you should worry. I bought an air purifier yesterday to help deal with the smell, but is there anything else I should be doing?

• Are there any other services I should be calling in the meantime that I might not be aware of?

• I read that, since it's likely the leaky pipe is the main water supply, I could potentially shut off the pipe entirely to minimize damage. Not sure if it's necessarily worth it since it would mean my neighbour and I living without water for the next five days, unless there's something I'm missing?

I'm feeling pretty frustrated and nervous about this whole situation, so any help you guys have to offer would be really appreciated. Thanks!