Rumbling thunder at night: should I sleep or should I run outside?

Only a few thunderstorms have passed Turku this year since I've been eager to try out some lightning photography. Last night there was a thunder storm that reigned for two hours, but the frequency of lightning strikes was not ideal for photography so I decided to close my eyes and go back to sleep.

A month back there was a great storm amply with lightnings so I decided to try out lightning photography for the first time. I hadn't read anything about shooting lightnings so I pretty much had to try out which settings would work.

Long shutter speeds are probably a good idea when shooting lightnings but I didn't have a tripod so I tried another solution. I selected a field of the sky and focused on infinity and kept the shutter going with one second of exposure for minutes at a time. I also took a video and picked the frames with lightnings, but the quality was farm from actual images(the last pic and video). Most of the pictures showed no lightnings, there where quite a few slight misses and a couple of successful ones. From total of over 400 photographs, these were somewhat successful.