[Clipper]

Brains Enough for Two can be played in that situation, but it only gives the helper in the combat a level. Player B was not helping in this situation, so they would not get a level and Player A would win the game alone.

If we take the situation that Player A wasn't beating the monster and thus was eligible to ask for help, Player B could become the helper and then play that card so that both players would go up to Level 10 simultaneously as you describe. In that situation, both Player A and Player B would share victory.