Usually the recording is physically there on the card, but because it was suddenly disconnected it doesn't get a chance to finalise the file, so the computer can't see it
I've managed to recover stereo wavs when this happened tho if you are using 4 inputs I am not sure, one time i recovered those but the audio was kind of interleaved together in some unusably messed up way. But it's surely somehow possible too tho, this was ages ago and I didn't know what i was doing.
Don't do anything more with the card (avoid recording any more on the same card in case it overwrites the lost data) and it should be possible to copy it as a disk image and use some software or other to extract the lost data.
