I'm confident that this isn't the lowest that Luna will get... Until UST is back at $1 there is a strong incentive to exchange it for LUNA and sell it...
You buy 1 UST at $0.42 and convert it to $1 worth of LUNA and dump it in the market making a $0.58 profit and further damaging LUNA's price.
There's a daily limit for the conversions but they're on a death spiral and I don't fuck around with falling knives. I hope the BTC reserves can save UST...