I do the same thing when I'm bored with material farming. There's a raised stone pillar back directly across from the Vault. I'll get up there, make myself comfy, and be the seventh man for teams trying to open the Vault. I'll snipe from distance, last night I even had to leave my perch and go from plate to plate like you did to help them out. I get waves of gratitude, and wave them "good luck" as they race off into the Vault. It's fun. I like giving them a good send off to start their big adventure. :)