As we got back up towards observing and entered the OMC_WHITENING state, I saw a guardian message that "ETMY HV ESD appears off". Looking at the suspension screen, I saw that even though the ETMY bias voltage was set, the H1:SUS-ETMY_L3_ESDAMON_DC_OUT16 channel was reading zero. Trending it back, I saw it should be reading something like 200.

Ibrahim, Keita, and I decided that the button we should probably press was the "HV ON/OFF" switch at the bottom of the ETMY screen which is the H1:SUS-ETMY_BIO_L3_RESET switch. Keita said "this is probably going to cause a lockloss" and I said "yeah probably" and then I pressed it and it caused a lockloss. However, I don't think we could have gone into observing like that, because that bias voltage is set to cancel out ground noise. In hindsight, Keita and I realized we should have probably: 1) set the bias offset to zero, 2) turned on the HV switch, 3) then slowly ramped up the ETMY ESD bias offset to the nominal value.