FO OF AN AMB SMT JET LANDED ON THE WRONG PARALLEL RWY DUE TO HABIT INSTEAD OF LISTENING TO THE ACTUAL CLRNC GIVEN BY THE CTLR. THIS MISTAKE CAUSED A C172 ON FINAL TO GAR.

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I WAS THE PF ON A VISUAL APCH TO ZZZ ON AN AIR AMBULANCE FLT. WE WERE A LIFEGUARD FLT AND ARE USUALLY GIVEN PRIORITY DUE TO THIS AND CLRED TO LAND ON THE LARGER AND CLOSER RWY (RWY 35R). WHEN APCH CTL HANDED US OVER TO ZZZ TWR MY CAPT (PNF) WAS WORKING THE RADIO AND THEY CLRED US ON RWY 35L. THE CAPT ALSO READ THIS BACK TO THE TWR (AS HE HEARD IN THE TWR TAPES). I WAS BUSY FLYING AND LOOKING FOR VFR TFC THAT WAS SHOOTING PRACTICE APCHS ON RWY 35R (ILS). I THOUGHT I HEARD US CLRED FOR A VISUAL AND TO LAND ON RWY 35R; SO I CONTINUED MY APCH TO RWY 35R. THE CAPT DID NOT SAY ANYTHING TO THE CONTRARY. ON A SHORT L BASE FOR RWY 35R; I SAW TFC ON FINAL FOR RWY 35R (A C172). I POINTED IT OUT TO THE CAPT AND HE AND I BOTH THOUGHT THIS WAS THE TFC PRACTICING ILS APCHS AND THAT THIS TFC WOULD BE GOING MISSED APCH. SINCE WE WERE MUCH FASTER AND THE TWR DIDN'T SAY ANYTHING EXCEPT FOR A TA; WE CONTINUED AND LANDED ON RWY 35R. UPON CONTACTING GND; WE WERE TOLD TO CONTACT THE TWR. THE CAPT CALLED THE TWR AND ALSO WENT UP TO THE TWR TO TALK TO EVERYONE INVOLVED.