No Macintosh HD in Volumes folder
Your main volume is encrypted with FileVault and still locked – consequently it doesn't show up in /Volumes. Before being able to mount it you'd have to unlock it:

diskutil cs unlockVolume lvUUID #replace lvUUID by the one shown in the diskutil listing


You will then be asked to enter the passphrase/password. You have to enter a passphrase or a password of a regular user eligible of unlocking FileVault. In your example the lvUUID is shown in diskutil list and starts with 573…. You may also get the lvUUID by entering diskutil cs list.