Why did this group of 6 people from the Treasury ask for unmasking on Dec 14?

Secretary of the Treasury - Jacob Lew

Acting Assistant Secretary Treasury - Arthur "Danny" McGlynn

Acting Deputy Assistant Secretary Treasury - Mike Neufeld

Deputy Secretary of the Treasury - Sarah Raskin

Under Secretary Treasury - Nathan Sheets

Acting Under Secretary Treasury - Adam Szubin

And then Lew made a second request on Jan 12.

Can anyone tell me if the viewing of the unmaksed document has to be done in a SCIF?