I don't know based on the rulebook. The provided context mentions an "optional rule for a 2-player game" (page 5), but the details of this rule are not included in the excerpts. However, the general rule for simultaneous elimination is given:

• "If all Monsters are eliminated at the same time... everyone loses!" (page 6)

But since the context also references a special rule for two players without providing its content, it is unclear if this general rule is modified for two-player games. To answer definitively, the full text of the optional two-player rule would be needed.

Source: Core Rulebook (pp. 1, 3, 4, 5, 6)