I asked the same question to one of my best guys that has helped me with the APT and is now one of the busiest guys in the industry and here is his answer:
Scenario, 4 way action, NLH tournament, Blinds at 500-1,000, action after the flop:
Player A bets 5,000 (leaving 45,000 behind)
Player B goes all-in for 9,000
Player C goes all-in for 13,000
Player D flat calls the 13,000 (leaving 50,000 behind)
Action back to Player A, who now re-pops it all-in for a total of 50,000, trying to isolate the 2 all-in players
Player D now goes into the tank!
Is there something wrong with the scenario?
1st player A cannot raise anymore, how can he re raise without any raise.
Instead of Player D flat calling the 13,000, he wants to min raise. How much can he min raise to and why?
2nd if player D wants to min raise it should be 18,000. (13,000+5,000)