Transmute Rock to Mud

[dredge]

So I have a rules question about Transmute Rock to Mud in conjunction with Transmute Mud to Rock.
Per say my druid is confronted with a medium sized human enemy in a cave. If I cast Transmute Rock to Mud on both the floor beneath them and the ceiling above them. (Note that it says they will sinks until hip- or chest-deep & the mud falling is said to spread out to 5ft depth in the spell description) Would said human then be encased in mud enough for my fellow druid to cast Transmute Mud to Rock and completely encase them?

[Mauril]

"Any creature in the mud is allowed a Reflex save to escape before the area is hardened to stone."

Because of the wonky way reflex saves work, if your victim makes his save, he's not encased in stone, though he really can't move until it is his turn.

However, yes, I would rule that even just the ceiling turning to mud and then being turned back into rock would be enough to encase a medium or smaller creature. This is because a medium creature (according to the rules) occupies a 5 foot cube (regardless of what height and weight you put in the descriptions).

You'd then start applying the suffocation rules.