Hollowmen are simples! I'm ranged - so as soon as you see the lights in the air, charge up force push and shock. The second before one of them hits you (should have about 10 within range) let her rip!
Out comes the rifle and its just a matter of shoot shoot shoot, reload and roll back, shoot shoot shoot. and repeat. By the end the big boy (who spawns other hollowmen) is in your face, have your last shot charged up (make it glow), when he's about to hit you, take the shot (or climb on his sholuders and blow his face off). Done, hollow men finished within the 30 seconds. Its quite a neat way to defeat them rather than just try and melee when you have 10 brothers coming at ya!