Question on thick filaments ? Also, will this force (pointing away from M-line) 'tear apart' the myosin filaments on M-line? If not, how can the filament withstand this force?

1. Yes, they are action-reaction pair.( Newton’s third law).
2. No, it won’t tear under normal circumstances. The filament withstands all that force because the attractive force between its constituents is far more than the force generated by myosin actin cycle.