Can you teleport outside? Sure.
Is it safe? So long as there's no rain to smudge your diagram it's basically as safe as doing it indoors. And in Lucien's defense there wasn't any rain at all, right up until the last sylabble of the incantation.
"Oh...."
"Basically everyone in my world would panic if they knew I was doing magic. And it's not like they're wrong to - cultists keep trying to destroy the world and dark magic kills far more people than mundane crime and I haven't actually heard of anyone who does as much magic as me and wasn't possessed by some sort of horrible madness or another. I've thought some about how to change this so I can sell people on resurrection once I get it but as it stands I have to keep everything I am doing extremely secret."
Nod. "I knew I was - taking a cost not just in lives but also in my - moral credibility, forever, but knowing it doesn't make it go away."
"I... still hope I live long enough that people change their mind about the sort of thing I've done. Unless I'm wrong about the tradeoffs being navigable in which case I'd prefer they find out and stop me sooner rather than later."