Shares of near-bankrupt companies have strong option-like characteristics, similar to out-of-the-money call options on the company's survival (because they are worth zero if debtors are not able to be paid off, nonzero otherwise).

If you know the basics about how options are priced the wild swings shouldn't come as a surpise at all.

Stocks at this stage are priced as options and bonds are priced as stocks; given that, nothing to phone home about.