This just happened to me this past week.
i was handling my ball and some clear mucus came out of his mouth and nose after tightly wrapping himself around me.
i cleared it away, put him back in his tank, watched him like a hawk over the weekend,no further signs of any sort of RI, but i still brought him to the vet on monday to find out he was in perfect health.
breathing was fine, most likely drank as mentioned above before being handled.
Forgot to mention, he is about to start shedding, that may also be some added stress to add to the situation and cause the regurg.