It might be....
---Killer buyer know lots of small buyers have long position for waiting breakup the resistance.
---Killer buyer Kill down the price to hit those small buyers' long position stop orders.
Let's observe this might be a cleaning followers strategy:
--If push down again to the region around 155 to 160 again and
--the price not breakdown and volume increased,
then it could be viewing Killer buyers change their strategy from sell to buy.