This is just WOW, some serious lightning. Nice job.
@Prism:
I usually open my windows to photograph lightning. My windows are set back into the wall by about 40cm so it barely rains inside (one shouldn't mind a few drops though), except for very rare cases.
Closing every other window and as much doors as possible helps to avoid the wind howling through the room.
Just try to find a window that is not much exposed to rain in storms and try shooting trough the open window.
Going outside is not really an option for me as I have no rain-proof place nearby.