Gamer Without a Cause
You haven't completed your mission yet! Remember, some documents were stolen from Jekserah and she will pay you to get them back. Looks like you'll have to venture farther into the dungeon to find those docs! (Scenario 2)
Changing from Scenario 1 to Scenario 2 will still trigger rewards based on the level difficulty you played on. You might not gain anything extra other than 'unlock scenario 2' and the achievement from mission bonuses, but every scenario you complete will give rewards based on the difficulty.