Let's say that we have a gaseous or liquidus compound (I don't know if elements or compounds make a difference, take this as a thought experiment), and we have a tungsten or steel block that's 5cm (or less, you choose) thick. Is there any physical method for that gas or liquid to pass through that thick heavy metal block (not by drilling etc.)?
If my question itself may be unclear, I can provide more specifications or examples if need be. My intention is to find out how deep a gas, or even just a tiny drop of some sort of liquid can penetrate through a heavy solid metal block, and why.

I'm just thinking of a scenario where a gas or a drop lands on the surface of a large thick metal shield. I know that's not a question that can be answered definitively just by
This is for a science fiction setting, in which this gas or liquid needs to be "sealed" within a confined space for narrative reasons, but I want to understand whether this is at all possible through real-science.

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I'll assume that you mean a stationary situation, i.e., that you don't want the heavy metal block to move.

If the compound is a gas under normal conditions (temperature and pressure),