The disk in question is disk04 - a 128 GB SSD drive in an external USB enclosure. I booted the Macbook from a X.11 USB install drive and there was an internal SSD drive as well. a simple fdisk ...
If the drive is relatively newish, it should support the ATA Secure Erase function. If so, use the manufacturer utility or another utility that supports ATA Secure Erase and it will wipe the drive ...