Hmm. Thanks guys! I think at this point I have 2 options:
1) I could wait for the 30 psi I shot in there (to seat the lid) to absorb into the beer and then attach the gas line with 10-12 psi to finish carbing. This way there's more pressure going into the keg than coming out and I won't get any in the line. Would this work?
2) Attach my bev line and pour off a couple pints. Attach gas line afterward and proceed with carbing as normal. The only thing with this is I usually don't carb with the bev line attached and it would be kind of a pain to remove it and clean it and reattach it later. I guess it would teach me not to do this again...
What is the best course of action? I'd rather do number one, but if there's some problem with that scenario that I haven't noticed, I'd rather learn about it now than after I go ahead and do it.