Is this a do over?

[ODog]

If you knew you (or your partners) had a count going, would you even blow this play dead?

Team B has now been put at a disadvantage, forced to execute another throw-in, presumably still in its backcourt.

Just count it out, and when you don't hear a horn after your 3 seconds are up, blow the whistle and the game is over. Sure, Team B coach has another second or two of exasperated yelling, but when he realizes he's won, that'll dissipate rather quickly.