[Fixed for V0.42] Monsters behind others can still melee

[R.K.]

When three monsters are on a tile, the one in back usually moves around a lot trying to get closer to the party. However, it occasionally makes physical attacks. This happened several times during a battle in the corridor leading to the fireball trigger and Delta room on level 8 (with extra monsters), and may also have happened in the Vorpal Blade skeleton trap on level 6.

[George Gilbert]

Fixed for V0.42

(and hello and welcome!)