LGT CONFUSED ON TAXI CROSSES ACTIVE RWY.

Narrative

AFTER PUSHING BACK FROM GATE I CALLED OHARE GND METERING TO INFORM THEM THAT WE WERE AT XX WITH INFO 'DELTA.' WE WERE TOLD TO MONITOR GND. GND CTL TOLD US 'RWY 32L T10 R ON BRAVO MIKE 2 MIKE TANGO' THAT IS WHAT I COPIED AND READ BACK. WE PROCEEDED TO TAXI ON 1 ENG. THE 3 OF US; CAPT; FO AND ENGINEER DISCUSSED THE RTE TO RWY 32L T10 AS THAT OF ARRIVING AT T10 FROM THE SE ON TANGO AS OPPOSED TO ARRIVING AT T10 FROM THE NE (VIA A6;J;J1;T) AS WE HAD ON OUR 2 PREVIOUS TRIPS TO OHARE EARLIER IN THE MONTH. AT ABOUT THE TIME WE ARRIVED AT THE INTXN OF MIKE AND TANGO WE COULD SEE THAT THERE WAS ONLY 1 OR 2 ACFT IN THE AREA. SO WE DECIDED TO START THE REMAINING 2 ENGS. ABOUT THAT TIME GND CTL GAVE US MAKE A R; A L; A L; AND A L. I AM NOT SURE OF THESE INSTRUCTIONS AS I WAS STARTING THE ENGS AND COULD NOT WRITE THEM DOWN. I REPEATED THE INSTRUCTIONS IN A QUESTIONING MANNER IN A ROUTING OTHER THAN HIS; BECAUSE IN MY MIND IT WAS DIFFERENT; AND I WAS HDG FOR T10. I AM NOT SURE WHAT HAPPENED NEXT BUT IT WAS THEN THAT I DOUBLE CHKED OUTSIDE AND SAW THAT WE WERE NOW XING RWY 32L ON MIKE SE OF T10 AND QUESTIONED GND AND HE ASKED US IF WE WANTED TO GO FROM MIKE OR MAKE 2 R TURNS. GND DID NOT SEEM UPSET THAT WE WERE XING THE RWY. I THINK WE (THE CREW) WERE ALL SURPRISED TO FIND OURSELVES XING A RWY (ALTHOUGH IT WAS NOT THE ACTIVE PORTION OF THE RWY). IN REVIEWING THE EVENTS I AM NOT SURE IF WE FOLLOWED OR FAILED TO FOLLOW THE CTLRS INSTRUCTIONS AND I WAS SURPRISED TO SEE MYSELF LOOKING OUT THE R WINDSHIELD AT AN ACFT ABOUT TO TKOF (ALTHOUGH AWAY FROM ME) FROM T10 ON RWY 32L. FACTORS WERE: UNFAMILIARITY WITH OHARE; RAPID FIRE INSTRUCTIONS; MY OWN PRECONCEIVED ROUTING RESULTING IN CONFUSION AND DOUBT; ALSO THE DIVIDED DUTIES IN THE COCKPIT OF TAXIING; COMMUNICATING AND STARTING ENGS.