Well, you obviously don't know what ur talking about, since time is the 4rth dimension and there's no magical 5th dimension around as far as we know.
And I'm not really sure what u mean with ur whole 5th dimension thing.
If u see space time as a volume, with T modifying the overall shape while going from it's origin to it's limit for example, you have ur causality and general one-way entropy nailed together with differences in relative 'time'.
well u could always use a fifth dimension as a unidimensional structure going through space time and being the 'present'.
But that's just very useless, and has so many logical flaws I just can't see it working for now.
As long as there's a differential between creation and end of a system, and a C as a limiting speed for transmition of information, you will have what you call Time.
and differentials go one way, until the system is evened out, and we go back to the void/meta singularity or verse or whatever else we came from