Having a sealed room has nothing to do with having negative pressure in your room.both ways produce neg. pressure in a sealed room.
Huh?????? you sure do give some confusing answers...Fluid dynamics, same law for;
low density fluid, our atmosphere
medium density fluid, water=1
high density fluid, maybe a volcano erupting.
None will pull but a tiny bit, All will push with million+ psi.
If your set-up pulls satisfactorily, then you're good to go within small margins at your location but as a design principle/application, results are unpredictable at untried locations if plan is pulling fluid rather than pumping.