If you ever get someone in a corner and your doing a gamma charge you can cancel that into Gamma quake . As soon as you hand hits the ground you can x-factor in the freeze buffer the command grab.
If the try to attack they get hit by the rocks if they keep blocking they will get grabbed.
I do this with characters that give me trouble or I know a player is good with then.
But its good to try to read your opponent. With hulk you know people are scared and going to wait to block and punish a St.H . But you have to make them afraid of the grab so if you know someone is going to try to block grab! Just keep at it it will come to you