Bookmakers and the Conservative Party Leadership Race

I notice it said on television that one Conservative MP had declared he would not run. The journalist said that he was the bookmaker's favourite.

Bookmakers run betting for various things where the result is not decideable by one person.

So how does it work if a number of candidates run in the contest, the bookmakers take bets on who will win, then, say, after the first round one is eliminated according to the rules, but someone who got more votes, than, say, three other people, decides that he or she will withdraw, even though he or she does not have to withdraw and could go through to the next round.

There seems no reason why an MP should need to take the bookmaking situation into consideration, but what is the situation for someone who has bet on that person winning the leadership contest?

Some of the media seem obsessed with odds that bookmakers are quoting.