Missions in Assassin's Creed Rebellion have very some interesting mechanics. Before entering any room you have to choose a hero, and after entering the room you have to decide what to do. These decisions usually differ only in the style of your playthrough: you can go in silently, without open battle or by challenging any opponent to fight directly.
Before entering the room you can check what chances the assassin will have in the room. Percentages appear over objects in the room. These percentages mean the chance to interact with them without any problems.
Percentage chances are marked with 3 colors: green, yellow and red. In the case of red, there is little chance that your hero will perform the order without any problems. It may happen that he falls into a trap (and lose some health points) or fall under the opponent's feet. In the case of yellow color, the activity should go without any problem. However, if you risk many times in a row, an accident may eventually happen.
As for the green, you have a good chance that your hero will perform the order 100% correctly and will go through the room without any problems.
The chances of completing a quest correctly depend on the level of the hero, their class and skills. That's why it's best if you check each hero before entering the room and send in the best one.