Maybe because I’d worked there before and had a dim memory for a prompt, or maybe just from a lucidity I could have used a few minutes earlier as foresight, I knew instantly what we’d done. In very tall spaces such as this, smoke detection as part of a fire alarm system usually takes the form of what are called beam detectors, a transmitter and receiver placed at opposite ends of the space at a height determined by geometry and building code. Electric eyes, in essence. If the beam is interrupted, as by smoke, the alarm goes off, and unless a pigeon gets inside, 40’ off the ground nothing other than smoke is expected to interrupt it. But the wobbling tip of our giant ladder just had. We leaned the ladder on the side wall and went outside to await Boston’s finest.As a national historic landmark, The Church of the Covenant merited 3 response vehicles, which arrived in well under 5 minutes. The captain approached us with that unique blend of aloof intensity, prepared to save a treasured building and/or its occupants but naturally expecting the ubiquitous false alarm. We told him what we thought had happened, which the annunciator panel confirmed, and after some fossicing about looking for the shutoff, a gaggle of firefighters assembled at the scene of the incident, gazing thoughtfully up at our ladder, now in its intended place and awaiting my attention.“I wouldn’t send anybody up that,” said firefighter # 1. “It’s not safe”“Yeah, that angle’s too steep,” said # 2. “See that symbol on the side? That should be straight up and down, not leaning back. You start to go up that, it’ll come away from the wall. You could fall. It’s not safe.”Mind you, these are guys who live ladders that are going to very not safe places and know their craft. But I’ve been many a dicey place on a ladder myself, albeit in theaters; wobbling side-to-side a couple of feet (literally) while 40’ in the air on the Loeb Drama Center’s old, massive, center-extension A-frames; snaking up into parts of sets on extension ladders set vertically; or hanging out over a 3-story drop on the Agassiz’s bendy fiberglass shepherd’s crook extension ladder hooked over the rim of the ceiling electrical trough. Besides, one simple fact of geometry was in my favor, as I earnestly explained to the assembled group of dubious clients and firefighters. Though 4’ or 5’ out from the wall IS indisputably too close to set the base when you’ll be 40’ in the air, it’s still 4’ or 5’ of space that’s INSIDE the ladder’s feet. I am indisputably getting wider, but I’m nowhere near that wide. The ladder’s entire (and considerable) center of gravity is to the wall, and once I got 15 feet up or so, all of mine would be, too. No way I could fall backwards, even trying. With someone ballasting it on the inside for that first bit, I was totally confident. Which made one of us.