Wet prime can certainly be a problem. Pulling your load is probably best, if it won't fire.
Years ago, I was hunting elk on the south fork of the Flathead River. Rain and show mixed all day, with heavy fog. I was refreshing the prime constantly, and was having serious doubts about it firing when needed.
I was heading back towards camp, and saw some movement in the brush ahead of me. I did a quick check of the pan, and saw a muddy mess in it.
Looking up, I saw a grizzly standing less than thirty yards away, looking directly at me. I stood there, considering the ramifications of a full bowel dump, when the bear fortunately decided I wasn't interesting enough to eat.
I waited for the bear to have enough time to move off, while drying my pan and pricking the vent. I was thinking I wished I had a cartridge rifle, rather than the .62 flinter that day.
As I was working on down the mountain, I saw an elk about 80 yards down the mountain.
I sat down, and took aim. I squeezed the trigger, and was rewarded with a flash in the pan. As I watched the elk wander off I was thinking I was sure glad I didn't have to shoot that bear.
I was still pondering this circumstance, when the rifle went off unexpectedly, a full twenty seconds after the flash in the pan. I made a clean kill shot on the stump in front of me, and had my trigger hand stuck under the opposite armpit, as it felt like my fingers had been torn off by the recoil. 180 gr, in a 7 1/2 # rifle will do that kind of thing.