Fache's dejectedly sitting in Teabing's plane, inspecting the abandoned cylinder when he receives a phone call.
It's Vernet. He explains the true story about what happened, (from his perspective, of course) and is merely trying to get the box back that Langdon and Sophie "stole". He's desperate to protect his bank's reputation.
Fache just reassures him that the box is in the safest of hands—i.e.: his.