Mask on

[Alligator Bag]

This play was brought up at our association meeting Sunday. Runners on 1st & 3rd, while pitcher comes to stretch, runner takes off from first presumably to get rundown and score runner on third, catcher yells to pitcher to step off and starts to take mask off. All of a sudden, pitcher comes home with pitch while catcher begins to stand. Catcher, realizing pitch is on its way, gets back down and catches pitch. What would you do?