In any case, there is no guarantee that they would fire you just because you fail the exams.
I thought there was. I dont know of anyone who failed the compre but got to keep the job. in my time infy (in 2006) gave a very generous exit for those who didnt clear the exams - they were allowed to resign and given 3 months advance pay and a 6 months workex certificate. given my limited knowledge of IT hiring processes, unless you're looking for another big co ( accenture, IBM etc) your background verification wont help much, and knowing b school hiring inside out, 6 months in infy on your resume will not matter either, you will still be treated as a fresher,and IT workex will not help you in getting into a college which is looking for a diverse profile. I didnt sign the bond (said my dad misplaced it

) Didnt get any salary during the period of training, but when the results came , I had a similar %ile, but lucked out on cutoffs and got no calls. Submitted by bond, and got my moolah
If i were in your shoes, i would flunk (I would also keep a very tight lid on the information regarding your calls, not even to your best friends ) why take a chance on an HR's goodwill?. Trust me most of the Line HR's in infy (or most IT companies for that matter) would not understand reason if it hit them in the face.
While maintaining good relations with infy is nice to have, its not essential. unless you are looking at getting into a tier 3 institute, and have IT as your aim/plan B, dont bother. Infy is laughed out of all tier 1/most tier 2 campuses. their B school profiles arent that good, and dont pay that well either.