BANG!
Lex used the hammer to smash down on space itself right before him, causing it to crack. Yet the cracks also began to heal the very moment they were formed. This place was not like BGY-987, the planet where the Midnight Battalion had waited for him.
There, the fabric of space had been frail and fragile, breaking easily. That was both a boon and a curse, for it made using destructive space techniques easier, and a curse because if he was not careful he would end up destroying a lot more than just space.
But here, the laws of space were whole and healthy, and so as Lex tried to break space, space itself tried to resist and heal. Technically speaking, if Lex wanted to just create a small fracture in space he would not need to take such extreme measures. But his aim was far larger than a small fracture, which is why he was doing things in a much simpler and brutish fashion. He was forcing space to shatter over a large area.