Theoretically you could have liquid methane on top of an ammonia-water mix in the temperature range of 176-190 K. Another possibility is ultra-cold liquid water, which is a denser liquid phase recently observed. Ultra-cold water had been predicted on molecular structural grounds, but is very tricky to observe, as ice forms so much more easily.

The first possibility makes me wonder. If the ammonia-water mix is relatively cold then the methane may be stable in liquid form above it directly beneath the ice, thus pressurised past its critical pressure (46 bar or about 3.7 km of ice on Titan) and providing a ready reservoir for driving explosive events if there's significant localised heating from deeper down.

Most modelling of the cryovolcanism apparent from RADAR studies of Titan involves the eruptions being fairly sedate affairs, but explosive decomposition of methane-ice clathrates could provide a lot of gas pressure ready to rip apart any weakness in the ice above.