Water-box is not passing completely from membrane

hiii… I’m new to LAMMPS. I’m simulation water solution with graphyne membranes. my problem is that after applying force to piston membrane with velocity and also applying velocity to water solution box it is not completely passing through membrane. can anyone please suggests me a modification? or guide me about errors in my input file. I’m attaching my input here.
thank you.
lammps.in (2.7 KB)