Interference calls

[Mi-Umpire]

Situation: OBR rules with modifications. I'm BU in the B slot. Dropped 3rd strike and the batter runs to first and is called out. On the throw to home to get R3 out of the corner of my eye I thought I saw him raise his arms up, the runner was about 2/3 of the way up the line. Second play, I was in C again and the catcher was up the line receiving the ball which dropped prior to the runner making contact with the catcher. Rules are either slide or get out of the way. Again out of the corner of my eye I thought R3 dropped his shoulder which I would of call interference IF I was the PU. My question is both of these were the PU call for interference and if he doesn't ask for help should of I motion for a conference with him? The catcher on the second play ended up going to the hospital for a possible separated shoulder. Thoughts???