It is way too much, but its how they've been training. to me 10km is essentially starting marathon distance, my thoughts on hearing that is why do that? I'm training for a fight, not a marathon, yeah may help, but 3 x 2min is a completely different ball park than 10km. Everytime you question them, you get back: "but the Thais do it".
I do well with 5km, once in a blue moon I end up hitting 6. The whole point of S&C is to supplement your skillwork, no point if its pulling you out and injuring you.
I find running to be the best as well, and outdoors at that. I'm able to work my heart and legs equally, compared to cycling where my legs burn out before I get the same amount of work done on my heartrate. Treadmill for me is too inaccurate, especially my gauge is by distance not speed.
Unfortunately when winter strolls down the block I have to use other methods, I usually end up skipping. I'm thinking of trying out swimming as its easier on the joints, and fun + a chance to mack Boise dimes at the right pool. I remember one time in Feb 2 years ago when it was -30 Celsius and dumbass me decided it was fine to still run. No problem, I have clothing and gear that'll keep me warm, and I warm up along the way.
Woke up at 5:30 AM, and literally 5 steps into the run I nearly KO myself slipping on black ice, then it was "NOPE".