What caused leakage in my cheesecake?

I made a cheesecake this past weekend. The firing schedule was two stages, cook at 350 F for 25 mins; then apply a sour cream top and insert back into oven for 5 mins at 450 F.

When I went to put it back in to brown the sour cream, I noticed there was a fair bit of smoke (although not enough to be alarmed yet). As I inserted the cheesecake, I noticed what seemed to be a bit of liquid on the oven liner.

As the sour cream toasted, I thought about what could have caused the liquid. I wondered if maybe something I cooked earlier (like a roast chicken) gave off some spatter. I became concerned that at 450 F, the smoke would become worse. Looking in on it, the smoke was indeed worse, and I shut the oven off and gave up on the cheesecake.

I am wondering specifically what caused the liquid.

I have some guesses, but I am hoping someone more experienced than me would be able to say for sure.

First, I will talk about the ingredients of the base cake, and see if that could have caused seepage.

The crust was an Oreo crumb, frozen (not baked), and there were several places where liquid could have gotten through.

The cheesecake itself consisted of:

• 1.5 lbs cream cheese
• 2 tsp vanilla
• 4 egg whites
• 1 C sugar

I am thinking one point of failure could be the egg whites. The directions were to beat to soft peaks, then slowly incorporate the sugar and beat to stiff peaks. When I separated one of the eggs, a very minute dabble of yolk may have gotten through. I thought I read that if there were any yolks, then it would be nearly impossible to beat to stiff peaks.

After I beat the whites and sugar for what seemed like too long of a time, I settled for what I told myself were stiff peaks. The recipe called to fold the whites into the beaten cream cheese. This may have been another failure point: I am unsure I folded long enough. When I took the cake out to top with sour cream, it showed definite segments of the cheese and egg.

And lastly I am wondering if the oven liner may have caused the liquid. That is, I think the temperature of 450 F was too high and am wondering if that temp caused the liner to degrade.

Hopefully someone knows what the cause was. I am looking to make this to an edible product.