How to handle?

[Rufus]

Had a situation last night where a ball was hit to our 2b who bobbles the ball, gains control, and throws to our 1b (full disclosure, my son was playing 1b). 1b makes a large split reaching for the throw, catches it, and holds the position. There were runners on base so the field ump was in between the mound and first (I know there is a term for the positions of the field ump, just not sure what that is). Field ump calls him safe and motions that 1b came off the bag (for what it's worth the 3b coach and bench coach of the other team - their bench was on the 1b side of the field - both came up to me after the 1/2 inning and said his foot was on the bag).

I started to go onto the field to ask the field ump what he saw and, assuming he would reiterate his call that 1b came off the bag, wanted to ask if we could ask the PU if he had a different view (there were other base runners so PU may have been looking at them - I still wanted to ask the question though). I knew that yelling across the field "Can we ask your partner if he saw it differently?" wasn't appropriate and so wanted to have the conversation in a normal speaking voice.

Before I got 2 steps out of the dugout the PU informed me that it was a judgment call and that I cannot be on the field. Not wanting to delay the game or, more to the point, get tossed from the game, I went back to the dugout.

My question is this - when, if ever, can a coach come onto the field to discuss a play such as this? Also, when, if ever, can you request that the umpire making a call see if his partner had the same thing?

Please understand that I'm not asking this just to get the call reversed. We won the game 14-9 so there's no bitterness or anything going on here. I'm more interested in making sure I don't waste time during a game with events such as this if there is no recourse. I also realize that sometimes officials get "straight-lined" or don't see a play clearly that the other official may. My intent is to try and figure out if there is a way/time to ask their partner for their view or if I just need to get over it and play ball.

Thanks in advance.