Here's a video of our squad killing Crota in about 4 minutes before spawning ogres. I used a hunter to be the sword bearer with full invisibility specs, and a titan came along with me to drop a shield. I jumped up from the center while invisible for the first run as fast as possible, and went to the rock on the right for the 2nd and 3rd runs,
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https://www.youtube.com/watch?v=i9u4gH02xx0