The teacher is sitting at the front of the room while children are working. It may seem like the teacher is taking a rest, but in truth, that teacher may be observing the room, watching closely to notice what's happening with regard to a particular student, group, or effort.
The child is alone in the hall. The teacher is not there. Why, you may wonder. Sometimes, a teacher may leave a child by themselves for a few minutes for good reasons. Of course the teacher has to believe that the situation is safe and justified, but again, things may not be as they seem.
A teacher may speak to a child with the kind of candor that seems abrupt, but unless you talk to the teacher to understand the roots of the discussion, it is difficult to judge the situation.
I guess what I'm saying is that none of us should be too quick to judge an educational observation without a conversation. Of course there are extremes, both good and not so good, that we can judge, but in general, it's not a good idea to judge a situation. Instead, ask questions such as what are your expectations or how can I help rather than assuming you understand what's going on. Lesson to self as well.