I had stepped out the control room for ~15min, and when I came back the first thing I noticed was a YELLOW "OK" on the GWIstat screen.  I asked around the Control Room to see if anyone knew why we were out of Science Mode (granted I should have announced my exit), but no one seemed to notice the drop from OBSERVATION. 

I took us back to Observation Mode immediately since there was no reason given for having us out.  I looked in the Verbal Alarm terminal, and did not see a note of the Intent Bit being changed.  (So, I've talked to TJ about getting this in the Verbal Alarm script.  And to also have time stamps attached to the Intention Bit alarms so we'll know when these come up.

Keita admitted he was the culprit; he opened a DTT session [which has an excitation], and then started it.  (We tested this, while in Observation mode, and we were able to open this DTT session, which had excitation selected, and this did not drop us out.  Robert & I thought that just opening a session would drop us out.  He mentioned that maybe this is the case with AWG.  We should test whether it can drop us out.).  So this is when we were out:

16:19-16:29UTC Out of OBSERVATION

Addendum:

Prior to PEM Injections, Robert and I wanted to check if AWG does in fact have a different effect with regards to staying in Observation Mode with Excitation channels.  Robert opened an AWG session (no drop), but once he merely selected an excitation in AWG, we were dropped out of Observation Mode.  This is even WITHOUT hitting the "Set/Run" button!

When you do this, the DIAG_EXC guardian Node gets an orange box and has the message:  EXC:  [system] excitation!

We were dropped out of Observation at:  20:10UTC due to this excitation being selected (and NOT run) (this was different from what DTT did).