Disconcertion always purposeful?

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HS varsity rivalry week in neighboring town. I am a spectator. Team B is up by two, under a minute to go and just coming out of a time out with A1 lining up for bonus free throw. Lane is set with B1 thru B4 and A2 and A3. As ball is made available to A1, B5 starts walking slowly from behind and left of A1, breaks arc and Trail shoots the arm out for delayed violaton. B5 continues walking and is almost at the free throw line as A1 releases the ball. A1 had to have had B5 in field of vision and it appeared so because the kid misses everything. Tweet, double lane violation, B was awarded the ball on the arrow and they go on to win. It looked to me that A1 was clearly disconcerted but does the disconcertion have to be overt and purposeful to be called that way? Very strange sequence at the end of a close game.