About half an hour ago, the Cypriot parliament rejected the deal. So back to the negotiation table.
The situation, as far as I understand it, is that two banks are in the danger of going under and need to be nationalized in order to save the savings. The alternative is letting them go under, which means that each person with savings needs to be compensated for his or her lost wealth (up to 100 k€). Which, technically, might be the cheaper alternative, but might create an even worse run on the banks in Cyprus, potentially leading to nearly 100% loss of savings.
As a detail, there's a few thousand British nationals in Cyprus, in the bases. UK is flying in money (1 M€ in cash) for them in case they can't use the ATM machines. Britain has also mentioned that they will pay the tax back to their citizens.
E: Flying in cash kind of underlines the catch-22 there. If withdrawals are allowed, then there's a chance on a run on the banks. If withdrawals are not allowed, they'll pretty soon run out of cash. Do I sense incoming limitations on how fast you can withdraw money from the banks?