1)
[Class time! either you are a student, observer, you just happened to ask the right question]
An important thing to understand in archeology is that not all myths are true. It is too easy to go into the Fallacy that I'd like to call: 'If Magic then Atlantis'. Always be skeptical of the accounts of ancient phenomena, People like to cast themselves as god-like beings, and their enemies as black-magic wielding cultists.
Look at the evidence you find in the dig, look for the mundane explanation before you start chasing after boogeymen. Trust me, it'd save you time and energy - since nine times out of ten, History is actually quite ordinary.
2)
[It's a sticky situation, a trap that could be sprung or has sprung but the results have yet to be seen, the man tenses as he picks up a rock]
Don't. Move. A. Muscle.
3)
[Oh Hi! Why is Indiana sneaking around in your private collection hall? Why don't you ask him yourself since you caught him at it?]
4)
[It's a Social call, Indiana pours himself a glass of bourbon and offers you some]
It's been a while hasn't it. I heard you've been having some trouble lately.