It depends on your SCSI bus configuration. If the Quantum drive is the only drive on the bus, it should be terminated. If you use an external drive on the 2091, then the internal drive should bot be terminated.
The scsi bus should be terminated at both ends. The card itself is terminated, so with an external drive terminating the other end, that's all you need. The short 'stub' to the internal drive in this case is OK.