In the opening shot...the music is instantly tension-filled...but nothing is happening onscreen....why give it away? When the guy is having his dinner and the 2nd hitman appears out of nowhere...I think it would be more appropriate if the music was calm...showing that this guy was not tense or that the audience should be tense or fear for the character....
Relaxing music...followed by a camera shot of the gun entering the picture would be more dramatic...than tension filled music followed by the guy breaking in and walking straight to the table and then an obvious far way shot of the guy pointing the gun at the main character....
The moment that the audience sees the gun is when the music should be tense...and I would not even show the 2nd hitman until he is pointing the gun...
my two cents...