I remember back when I was in SMM one of my instructors had bad blood with another instructor (who is more senior than he is). Even so, my instructor was professional enough to not let it get in the way of trainees' training and welfare.
Not so for the more senior instructor, though. He would find all sorts of ways and means to get to my instructor, to the point of finding fault with us trainees.
Once my instructor was marching us to the cookhouse for lunch. My platoon IC failed to give the proper commands to stop, so we screwed it up. He then rectified the situation by ordering us to hentak kaki. My instructor said nothing, and shrugged it off as a minor issue (which it is).
A few hours later, after dinner, the senior instructor ordered the whole lot of us to fall in. He then f**ked us up left right center in front of the entire school and made sure that my instructor was watching. After a long period of tekan, he said that his reason for tekaning us was because of that 'screwed-up stopping drill during lunch time'.
We all got tekaned like hell for quite some time, and booked out later than the other platoons. My instructor, shame-faced, told us that the senior instructor had tekaned us as a means of getting back at him, and that he felt bad at not being able to do anything about it.
That was only one incident where the senior instructor tekaned us just to get back at my instructor. There were many more incidents, but you get the drift.
Damn that bloody senior instructor. He should rip off his 2SG rank immediately. He certainly doesn't know the meaning of the word 'professionalism'.