This is another what if hypothetical moment had my OC Bambo been in the first movie.
For this one it's after the gang break up and go different ways after falling out with Littlefoot and are walking along the path over a larva pool.
Now what I thought what came before hand is Littlefoot and Cera have their big argument and fight (which I would tone down quite a lot for this hypothetical version ) and also for this I take reference from the original script were after Littlefoot and Cera's scrap, Littlefoot takes his anger out on the others. For Bambo when he tries to reason with Littlefoot when he yells at Cera they never wanted her with them.
Littlefoot shouts at Bambo thinking he's taking Cera's side if so he should go with her. Bambo while hurt and upset by this, knows better then to talk back to Littlefoot and reluctantly leaves, then like in said OG script Littlefoot also take it out on Ducky, Spike and Petrie telling them they've been liability's and they should go and find the great valley on their own.
Cut forward to when their in the larva pool path, Bambo while upset about What Littlefoot said to him, feels like it's partly his fault for what happened, thinking that if he'd acted quicker and stepped in back when Cera said she wanted to leave the whole dispute may not have happened as Bambo is a fellow three-horn and would have listened to him. Also even though Littlefoot was hard on and walked out on him and the others he feels very unsafe without him.