Stuck in a restriction

Was diving a cave the other day when one of the team members, prior to mine, got stuck in a restriction going in. I entered via a different restriction to the left of the standard entry, and tried pushing with all my might to push him back out... Couldn't.

Was contemplating cutting his harness shoulder straps when my partner, having followed my silt, showed up. Together we tried again, wedging ourselves against the rocks/ceiling, and succeeded in pushing him back. His argon bottle (he was wearing doubles) was the reason he couldn't enter, not sure if that was reason we had so much problem pushing him back out though.