In SBO there is no way to view a b3's array element value
In Continuum there is a command line that allows printing array elements by specifying the array index
b3 BACnet devices.
As of version 1.8 no such interface has been implemented in SBO.
Per SBO road map version 1.9 of SBO will provide an interface to view b3 array/log element values, for prior versions, a work around can be used.
A workaround is to use a Script program to expose the array element value.