"I thought I could get out of it," he writes, scowling, and meaning the world of paranoia "but its shadows dog my heels." He hesitates, and adds, "How probable? I find two destructive incidents in a month, both within certain person's area of announced intention to expand, probable enough to lay down protections. However, I admit to trusting my intuition--as I explained it to you," he finishes, putting down his pen with a look at Holmes.*
With only a brief glance at Albus, he conveys the thought/question that his own Headmaster had understood when he found it necessary to act on information he'd promised not to reveal...?
* With whom he'd established that intuition was to be defined as information assembled by the subconscious into a picture clear enough to be guided by.