Can I take a break of a minute or two between sections? I mean taking a deep breath after completing VARC and before starting DILR.

that the main purpose of giving mocks, you make yourself accustomed to the spontaneous three hours of mind engagement. however, those 120 seconds play very crusial role in making or losing an IIM call. however, its the choice of an individual. if you are really exhausted after a section or two, you must take a breeak, else continue. the good news is that on the d day, the adranalin rush will be at peak. if you go with a healthy mindset, your FIGHT OR FLIGHT response would select FIGHT instead of FLIGHT, on contraray if you go with leathargic mindset(just for the sake of giving exam), it will select FLIGHT.
a smart candidate does not attempt all the questions in a particular section. varc section would be the most enguaging, however, in second section.,you might find ample of time to take few deep breaths before proceeding to quants section. make yourself accustomed not to take any break in the first juncture of the paper, that is between varc and lardi.
NOTE : whateva i said above is subjected to personal openions, its advisable to sit in the exam with your own tried and tested stratergies..
cheerst to cat 2k19

I wrote cat 2018, and i can say that in the actual cat u will be given a break of 2 mins for each section

That's completely up to you but just know that you'll be missing 2 minutes of the next section. It depends on how you see it, you might do really well considering you calmed yourself down or you could really mess it up thinking that you wasted some time . remember in two minutes you can miss a whole question. see whatever suits you

Hi, the next section will start automatically after the present section without any gap.