Ash's nade will only explode if they hit a material (wall, floor etc) and even then it has to be a material on which you could put breaching charges on anything else and it won't work, and the only way you can kill someone with it is if you hit the wall behind the enemy with it while they are really close to it. Anything else and the grenade won't work, you could make a direct hit to an enemy and it won't do any damage.
The walk key is basically there because you cannot have the variation in movement that analogue sticks provide when you play using keyboard and mouse, since when playing with a controller you just tilt the analogue slightly to move slow. Also walking still makes sound, even staying at one place and merely turning makes a sound.
If you are on now then I can join.
