I see youtube videos before the attack:
all soldiers sit around fireplace and relax
http://youtu.be/z9sVlYtNSaY
later bus drove by and see tanks on fire and destroyed
http://youtu.be/t5QhbTaWDB8

and here is another view of it:
http://lifenews.ru/news/133652

maybe they got punished by their own because they refuse to kill civilians ?

edit:
most likely their own if anti kiev = separatist = pro russian units they would capture the tanks not destroy.
someone say killing happened at 5 am from nearby local village, how daytime is 5am?
http://youtu.be/O9ySXaRu04k
I believe the 2 helicopter killed them not separatists from nearby village.
now they say nearby village did it so US/Nato/Kiev backed soldiers can come and wipe out this village.
more shelling follows be careful and stay safe !

if you look at this and scroll down a little in comments you see Kiev soldiers look like blackwater:
http://lifenews.ru/news/133652#comments