Sounds like a harebrained plot. If someone wanted to kill Hitler in a suicidal manner, all that would be necessary would be to pull out a Luger and shoot him. The shooter might even get away with some luck.
They put a bomb on his plane disguised as a bottle [or bottles] of brandy. Failed to detonate.
But bombs in suitcases are sexier though (Cue 1940s music playing in phonograph)
Hitler's guards were elite professionals with what seemed a sixth sense. Albert Speers once thought of gassing Hitler's bunker. The next day the air vents were extended fourty feet above the ground, surrounded by wire, and guarded. You can bet that nobody could bring any sort of weapon close to Hitler.