How the bookies knows that 3rd Qtr in LAC@MEM match will be under 45.5?

From pre match odds , it is clearly suggesting LAC@MEM will play boring 3rd qtr to make it under 45.5 ..

Did both teams sell info on some part of the match in advance ?

Its now just halfway 2nd qtr ...those who need money , can try on Under 45.5 3rd qtr bets at the bookies ...Its like free money