How does a bank call a note? What is the WORST case scenario?

[Mykael Williamson]

I suppose I could have just as a easily titled this: How did people go bankrupt in 2008?

Here is my question, I am new to real estate investing and I understand from the BP community that leverage is the key to expediting wealth.  However, there is a need to be responsible with leverage and mitigate risks when possible.  

My goals: I want to wholesale property while I learn, next step is use my day job capital to flip properties, then finally use that revenue from flipping to purchase buy and hold rentals until I can fire my day job.  

I read J Scott's posting on his strategy with leverage and how he likes to be in at least a 30% equity position at purchase.  So I guess what I am asking is, if a property that I am holding has positive cash flow...a healthy 6 month reserve behind it...and I am at a 30% equity position in the property, what is the WORST that can happen?  

1. Can the bank go under? Since they failed, do they have the right to call my mortgage due forcing me to sell the property?  I could see that being pretty bad, especially if the property had depreciated more than 30% requiring me to take a loss on the sale.

2. I suppose the job market could dry up and there could be no tenants to be found or rent rates could decrease making the property negative cash flow for longer than my 6 month reserve?

3. I guess the tenant could loose their mind and destroy the place before they leave, creating damages that far exceed my reserves and CapX reserves. (hopefully my property management company would follow @Chris Clothier's model of building great relationships to hedge me against this risk.

What else could go wrong?

Thanks everyone!