I'm gunna be lame and select prompt #2. Whether up by one, down by one or tied it's always a bit nerve wracking in the dying minutes of the game. That being said I think the most tense would have to be down by 1. Especially when under the circumstance that you shouldn't be down at all haha. When you're up by one there's obviously a bit of nerves of "what if" they score, but worst scenario it leads to a tie. When it's tied you obviously don't want to cough up the lead, but if you can get the game to overtime you can at least snag one of those loser pity points. When you're down by one you're in the hot seat. The magnifying glass is on your every move. You need to come up clutch to tie the game, let alone give your team a chance to win.

Side note: If chel has taught me anything, 2 goals is the worst lead in hockey. So maybe up by 2 is the worst (most tense) place to be? Something to think about.