Compare Joh 5:10, and note the different word for healing. See references there.
Who it was (τίς ἐστιν)
The present tense, who it is.
Had conveyed Himself away (ἐξένευσεν)
The verb means, literally, to turn the head aside, in order to avoid something. Hence, generally, to retire or withdraw. Only here in the New Testament.