This proposal is a continuation access to a recent experiment conducted at OSIRIS (RB1510529) to study the quantum tunneling characteristics of ZIF-8, which is a cubic metal-organic framework adopting a sodalite architecture. We will employ quasi-elastic neutron spectroscopy (QENS) to investigate in great detail the effects of varying gas dosing (pore filling effect) on the quantum rotation behaviour of the methyl groups present in ZIF-8. The results are essential to the completion of our recent study, specifically to enable detailed understanding of the mechanism(s) responsible for tunnelling response of Ar and N2 gas. This work may open up new science towards leveraging the emerging field of quantum molecular rotors in the context of metal-organic frameworks (MOFs).