With 150% hindsight and making no judgements whatsoever for all professionals involved going about their duty ….
So far the situation looks like –
Geneva ATC had their ATC conflict alert off for maintenance.
The sector should have been manned by 2 ATCOs and only one was there. The second ATCO had actually left the building.
Geneva accepted the Russian aircraft at FL360 on a track which directly conflicted with the DHL in the cruise at FL360 and under their control. Normal separation for crossing tracks at the same level would be at least 10 minutes. (If aircraft were on direct routes the advance warning of confliction on Flight Progress strips may have been less obvious or non existent)
Swiss ATC said initially they instructed the Russian to descend 2 minutes before collision. That has now been revised to 50 seconds. ( A time now probably measured to the second from RT tapes)
So far it is not clear what phraseology was used for the avoiding action descent.
It appears no avoiding action was given to the DHL when a hard right turn would probably have been an appropriate option.
The Russian crew did not acknowledge the first call but did acknowledge the second and was descending.
At the same time, if his TCAS was serviceable, it would have been annunciating the RA “climb, climb” as a consequence of the “descend, descend” RA to the DHL.
It is likely then that the Russian was receiving conflicting resolution from ATC and TCAS.
Spoken to in his non native tongue, with less than 50 seconds notice he assimilated two avoiding action instructions, disengaged the autopilot and took the ATC avoiding action and managed a descent of about 500ft.
The simultaneous and similar TCAS and ATC avoiding action kept the aircraft in conflict until collision.
One big lesson pilots may take from this scenario even if not 100% accurate - never, never, never choose not to follow a TCAS RA no matter who tells you or what you think is correct.
Hopefully the industry will not allocate blame but talk about cause.