His mouth tugged into a tiny wisp of a grin as he saw the true personality of the other Doctor shine through, though he found it difficult to concentrate on both trying to keep the mania at bay and watching the figure through the glass barrier.
So, his theory was correct: it was definitely possible for an incarnation's mind to influence another's, perhaps even attempt to heal it, make it whole and hearty again. But he was only a single Time Lord, and one of the psychically weakest of his incarnations at that. If...if more of the incarnations worked together...perhaps...perhaps...perhaps...
...perhaps...
...perhaps he'll finish this thought after he'd recovered from this fainting spell...
He slumped to the ground, his overtaxed mind seizing up and refusing to function, the barrier against the other Doctor's madness collapsing away along with Five's consciousness.