Nobody bought NR because they couldn't borrow the money to do so; that doesn't mean NR isn't solvent. Several banks were interested in buying it, and were convinced it was solvent, but the inter-bank lending just isn't working properly at the moment, so couldn't do so. The BoE only agreed to the emergency loan because they were convinced it was solvent; they would not agree to emergency loans to cover the purchase.

I absolutely agree we shouldn't bail out NR if isn't solvent - that's not what has happened, and not what has been proposed. I think promising to cover all depositors was probably not the right choice, but a continued run on the bank was a bad option.