Steal a level and winning

[Palmer]

Then general rule is "Once something has started, everything else has to wait until it's done before they can happen."

As soon as Divine Intervention hits the table, it has to finish granting the level (and thus the win) before any other cards can take effect (by that point, it's game over anyways).

The only exception is any card that says it "cancels".

The second scenario is much as you describe. It really comes down to whoever declares their intentions first (most likely the orc). It should not come down to a frenzied shouting match though.
In the event of people wanting to do things at the same time, a simple rule of thumb is whoever's turn it is gets to go first. Which is the orc.