Wow that was huge! Where was your plant before it broke? (inside/outside.) When you tried putting one outside, the leaf that died may have just gotten sunburned after being inside for so long (an assumption.) Diefs are pretty wimpy about direct sun, if any, it should gradually eased into it, starting with just going outside in bright shade for a while, then to a little sun if you want, early AM or late PM. Sunburn can't heal though, (and doesn't usually hit the "would have cut it off soon anyway" leaves,) so keep that in mind.

Whether or not to change from water to soil depends on what you want. If there are a lot of roots, I would trim about half of them off before changing from water to soil. Pics would help a lot with more specific advice.

Did anything grow from the original broken stems/trunks?