It sort of suggests (being very careful here), that the teams first expedition into the temple goes somewhat undramatic - they all come back with stories to tell - and Holloway with an infection that he presumably first notices when looking in that mirror. Or he gets the infection somehow onboard the Prometheus - the exploding head, David messing about with one of the urns...
When everything goes to hell, it could be a different/the next expedition - Milburn getting some frenchkissing, Fifield getting some love too. Hence they return in bad shape and cue the scene with Vickers setting some of them ablaze, cue Fifield going beserk in the bay area...
It sort of makes sense in context with the scene with David, Shaw and others entering the Juggernaut control room - remember Davids fresh remark. This could be part of the first succesful expedition - them entering the ship without actually realizing it's a ship but thinking it's part of the temple. We've seen that the two are connected by an underground tunnel in the HD shots of the temple scan. It makes sense, because the team are so intrigued but relaxed in that scene, explorerers - no sensation of danger at all. Shaw doesn't look like a person who just witnessed her boyfriend being toased, not to mention all the other shit that goes down...