How about "drops through gaps between objects that, upon close inspection, should have been completely impassable to him" instead of phasing through solid objects?
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"You know how parents tell you everything's going to fine, but you know they're lying to make you feel better? Everything's going to be fine." - The Doctor
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"You know how parents tell you everything's going to fine, but you know they're lying to make you feel better? Everything's going to be fine." - The Doctor