Hey, Get up seems kind of useless -- by the time you get it, the chance of surviving an attack at 0 to -9 HP is going to be fairly low. In general, abilities based around that are just not very good, because it doesn't come up often enough to be worth it (and, what, at most it is an action to give a tiny number of temporary HP? Not very good even when it happens. The fact that you can only use it when you desperately need -- and not, say, before you're about to die-- is a flaw, not an advantage.)

Unless you mean for it to have the ability to bring back the dead, but that seems unlikely. (Although really, perhaps some form of an ability similar to Psionic Revivify once per day would be good.)