As many of you know, options can get super wide in a fast market. I looked at the data for 8/24/15 and the SP was down 100 points (about 5%) at one point, so obviously his short puts were getting hammered.
When these automated liquidation algorithms start running, they just dump market orders out there. It's not hard to watch a B/A spread go from $4.50/$6.00 to $0.15/$85.00 in a millisecond as the computers add/remove orders. I've always felt like that was the unfair part of the entire process - that you could have a contract worth maybe $5.25 and it gets liquidated at $64.00 or something unbelievable.
I'm not saying that happened here, but it seems possible.