If by some miracle I manage to get a big stack of chips then I will leave the table for an hour and come back to play in later stages.
Is that a legit tactic?
Is this why people are going to sit out in the other tournaments, I'm playing in to learn it?
First of all, sitting out is never a legit tactic. Especially as a beginner you should start to convernt your cip counts into big blinds (in your head) -
the more blinds you have the more pressure you can put on your opponents and the more hands you can play. That's why should try to increase your chip stack at all times of the tournament. Sitting out for an hour or more gives you a huge disadvantage, because the blinds will go up and it will be easier for your opponents to put pressure on you (since they were able to increase their stacks, while your were sitting out).
Let me give you a rough (basic) example, e.g:
Player 1 has 50000 (100BB)
Player 2 has 3500 (7BB)
Player 3 has 4000 (8BB)
Player 4 has 1000 (2BB)
Player 5 has 4500 (9BB)
If you're Player 1 here and you get the chance to open raise, you could basically push "all-in" any two cards and your move would be mathematically correct. Many beginners make the mistake that they fold far too many hands, especially in the final phase of the tournament, because they are waiting for good hands. If you drop to a lower stack (e.g. you only have 15-20 big blinds left) your range of playable hands gets smaller and smaller. You should switch to a "push or fold style" with that kind of a small stack.
If you are interested in Poker, I suggest you to check some basic (beginner) Poker videos on Youtube. If you spend a few hours to learn the basics, I am sure you will be able to play most of the (fun) tournaments here on BitcoinTalk profitable on the long run.