trapped in the lighthouse with an armed maniac

We followed Tuppence's advice and struggled out into the howling elements to rescue the coracle. Luckily for Tuppence, he was sporting full gale-style protection kit, viz. an oilskin coat which reached to his ankles, seaboots, and a matching oilskin hat. Geoffrey and I were less fortunate. Of course, my wool does contain lanolin, and Geoffrey's feathers have waterproofing, nevertheless we soon found ourselves shivering and soaked through as we battled across the slippery seaweed covered rocks to the shingle beach where we'd stashed the coracle.
Eventually we managed to drag it into a cave high above the tide line, where it should be safe enough.
After, we restored ourselves with some emergency madeira and cake rations beside a crackling driftwood fire, inside the lighthouse.
"But what on earth are you DOING here, uncle Tuppy?" queried Tuppence, fixing me with his most piercing and disapproving gaze.
"I might ask you the same question, nephew," I replied, refusing to be intimidated by his stare.
"Can't say," he said curtly. "Top secret. Special ops."
"For goodness sake! don't be so melodramatic!" I snapped, then instantly regretted my loss of self control as Tuppence threw off his oilskin to reveal a brace of pistols stuck into his belt.
"Don't worry, uncle Tuppy. I won't use them. Unless I HAVE to."
Geoffrey and I exchanged glances. Tuppence was even more power mad than ever. We would need to take steps. Either that, or leave the island asap.
As soon as Tuppence nodded off by the fire, Geoffrey and I had a whispered confab.
"We can't let him go around behaving like this, Tuppy! Carrying pistols, and throwing his weight about! He's completely deluded! he's going to end up in the hulks!"
"Hold on a minute, Geoffrey. We don't know who's pulling his strings, do we? For all we know, he really could be on special ops.."
"Rubbish! he's bonkers! let's get those pistols off him while he's still asleep."
Suddenly, a hail of shot blasted into the lighthouse wall, and the initial T appeared in bulletholes above the fireplace.
"You fools!" laughed Tuppence, twirling the smoking pistols then sticking them back into his belt.
Geoffrey and I backed towards the door as swiftly as possible under the circumstances. Trapped on Flannan Isle, with a maniac armed to the teeth? there was only one thing to do...
RUN!!!!!!!!!!!!!!