A shoot out is generally conducted in a knockout STT format. The winner (and sometimes 2nd or even 3rd) on each table go into the next table draw and so on until the final table. Stack sizes and the level clock are normally reset at the start of each table round.
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Say you have 100 in a shootout tourney, 10 tables of 10.
Each table is a stt, and the winner from each stt goes to the final table of 10.
The advantage of this is that there are no table moves (until the final) and therefore you can work your table out, and just beat your table.
On the biggest poker sites shootouts are a popular way of satelliting into their big Sunday events.