Okay you need to do some reading.
Order book example of your 46 bid/50 ask.
43.00----- 4 contracts
44.00 -----3contracts
45.00------2 contracts
46.00------1 contracts.
47.00----- none available
48.00------none available
49.00------none available
50.00------ 2 contracts
51.00-------6 contracts
52.00-------3 contracts
Etc
Now with this example the current NBBO( national best bid offer ) is 46/50
Bid46/50ask. And for simpler well say there's two types of orders. Limit and market.
If you wanted to buy 1 contract right away (market order)at the best price, with that order book shown, you'd receive 1 contract at 50$. If you wanted to sell an order right away( market order), you'd sell at 46.00.
Now if you wanted more then 1 it would run through the book. Say you want to sell 6 contracts right now( this means using market order you'll be filled instantly at whatever the book has. You could get filled very poorly passed the last quote if markets move fast or dry up in liquidity) so at 6 contracts your you'd end up selling one at 46, two at 45 and 3 at 44.
Now if your willing to wait and have a price you'd like to get in you can use a limit order. So you want to buy but you don't want to buy at 50.00. You could enter a limit order anywheres and wait for markets to move your way as orders go through the book. You could also maybe go above the best bid(buyer) who is at 46.00 right now or place a limit above at let's say 47.00. Your now the best bid. Nothing says this will fill as markets can quickly go up and limit orders will be placed higher then yours putting you behind the queue .
Nobody's defending TOS. You just have no clue how markets work.
That was a very simple example and go read some more on order flow or something.
With this example where do you think TOS could get you your contracts at 46.50 in your example? No one is willing to buy there. At the moment you sell with your market order the best buyers price is 46.00.