Pretty much everywhere any contact or other NPC uses the word 'debrief' they actually mean 'brief.'
Brief means to give someone information (which is usually what they are doing).
Debrief means to ask someone for information, usually after they complete a mission.
E.g. Mish briefing from Infernia in the finale of Who Will Die, she says, 'Lady Grey wants to debrief you before you go up' but Lady Grey doesn't ask me stuff; she tells me stuff.
Also, when talking to Lady Grey before that last WWD mish, she says, 'I will be providing you magical protection which will allow you to breath in space.'
P.S. Whoa, they got one right! Pandora's Box, The Clamor and the Clangor, mish 2: After the previous mish didn't go as planned... 'He'd like you to report to Fort Trident to debrief with his team.'