BrookM wrote:Marines can only shoot straight ahead, not diagonally.
I am afraid you are mistaken.
The first line under the line of sight rules is paraphrased as stating that in order to shoot something, you must see it. In other words you can shoot whatever you can see.
The three example diagrams that follow the line of sight rules pretty much explain why you can shoot a model around a corner one space away.
Lets look at the Line of sight diagram for a moment:
Notice how line of sight isnt simply straight ahead but at a 90 degree angle to the models front facing.
In the next example found in the rulebook, we see that the marine with the green check mark can see the Genestealer around the corner, but the marine next to the red X cannot:
Likewise the same thing in this example. The marine next to the red X has its line of sight, from anything other than straight ahead, blocked off by the walls of the corridor, while the marine inside the entrance to the room can see the Genestealers due to both models being inside unblocked line of sight:
All of the above diagrams are found in the rulebook.
Now lets put this principle in practice using the old 5 x 5 space room tile found in the deathwing expansion:
The yellow spaces represent the marines line of sight. All of the Genestealers make move actions in the order of the numbers provided. At no time is line of sight blocked to Genestealers numbered 1-4 but when the Genestealers numbered 5-6 make a move action, they cannot be killed by overwatch fire because they have ended their action outside of line of sight.
Make any sense now?