21 January 2018 was TSHRTW post (:45 minute marker).
TSHRTW in baseball was October 3
The Emergency Broadcast test was October 3
The other SHRTW posts have a :45 as :MM or :SS
The posts from April 6 (also at :00) are on there just because of that.
:30 is the first RED OCTOBER date on the QClock. (November 7/17)
:00/:30./ are bisected by :45
That was why I added/connected them on the QCLock.
Hope that helps