AN ACR MLG RESPONDED TO A TCASII 'MONITOR VERT SPD' COMMAND BY TURNING. THIS CREATED A REDUCED SEPARATION WITH ANOTHER ACFT. ALL OF THIS HAPPENED IN THE BUR TFC PATTERN.

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DURING OUR APCH TO ILS RWY 8 AT BURBANK; CA; OUR TCASII DISPLAYED NUMEROUS AIR TARGETS IN THE VICINITY OF THE ARPT. APCH CTL WAS EXTREMELY BUSY AS WERE WE COMPLETING THE PREPARATIONS FOR LNDG; COMMUNICATING WITH ATC; FLYING THE APCH AND RESPONDING TO THE 2-3 TA'S SOUNDED WITHIN THE FEW MINS UP TO THE INCIDENT. AFTER INTERCEPTING THE LOC AT 3000 FT; AND INSIDE OF 'SILEX;' WE RECEIVED ANOTHER TA FOR A TCASII TARGET AT OUR 11 O'CLOCK; BELOW US AND CLBING. WHILE VISUALLY SEARCHING FOR IT; THE ACFT MOVED TO DISPLAY -- 300 FT AND CLBING AND CLOSING ON OUR POS RAPIDLY. AN RA 'MONITOR VERT SPD' WAS ISSUED BY TCASII; AND OUR TVSI INDICATED RED LIGHTS BELOW 0 VSI. AFTER SEVERAL MORE SECONDS ATTEMPTING TO VISUALLY ACQUIRE THIS CLOSING ACFT; THE CAPT MANEUVERED A R BANK TURN APPROX 30 DEGS R OF FINAL APCH COURSE. THE THREAT ACFT WAS NEVER SPOTTED. AFTER TURNING R; APCH CTL STATED THAT WE TURN BACK IMMEDIATELY AND THAT WE HAD CAUSED A LOSS OF SEPARATION ON AN ACFT AT OUR 2 O'CLOCK; OPPOSITE DIRECTION. I SPOTTED THIS ACFT AND ESTIMATE IT TO HAVE BEEN 1 - 1 1/2 MI AWAY; SAME ALT. AFTER OUR TURN BACK TOWARDS FINAL; WE ELECTED A GAR BECAUSE WE WERE TOO HIGH FOR A SAFE APCH DUE TO THE MANEUVERING. WE RECEIVED VECTOR BACK AROUND FOR AN UNEVENTFUL SECOND APCH AND LNDG. I BELIEVE THAT WAS A VERY UNSAFE SIT FOR A PAX ACFT TO BE IN AND THAT THE CAPT EXERCISED GOOD JUDGEMENT TO MANEUVER AWAY FROM THE THREAT. THE APCH CTL FREQ WAS OVERLOADED AND WE WERE UNABLE TO ISSUE A WARNING OF OUR EVASIVE ACTION.