Hello, I am not saying this isnt a cold,(does that make sense, its a double negative) but aldabras do drink through their nose sometimes causing a nasal discharge like you are describing for several hours. Also if the tort is getting too hot(or too cold) it eyes may water running down over the face and getting blown away from the nostrils during exhaling like a runny nose would. You or your vet will have to decide whats going on with the tortoise and if it is a cold treat it accordingly. Hope this hel[ps in some way and good luck with it! (did you happen to notice if it was drinking from the water bowl on the days it happens?)