I haven't seen The Silurians yet, but I feel that the Doctor always does have a degree of wisdom, over humans at least, that comes through when it's really important; at the same time, however, when things aren't dire, the Doctor becomes very childlike. I think this is established in Spearhead from Space, Three's first episode-- there is a really interesting dynamic between the Doctor and the Brig in that one-- in so many ways, the Brig must take on the role of parent/schoolmaster, yet they need to be able to switch that around quickly in an emergency.