As the party sets foot on the stairs, the shield lifts to its sentinel position. It takes no further actions… at first.

But as they close in past 10 feet, a snap is heard - a sound like leaping static or a circuit fizzing. The shield pivots, directing its front to the team members closest to it, and rushes forward to Ram them.

(The attack is physical and low damage at this range and speed. Protect dampens it further. But you may take additional damage from falling against party members and/or the stone steps.)