You cannot take any vehicles inside of a bank / store during a robbery.
Respective Robbery Limits:
House Robberies/Store Robberies - Maximum of 3 people involved and 1 vehicle on the scene. No outside assistance, only the people on the original scene are to be involved.
Train/Yacht/Armored Vehicle Robbery - Maximum of 4 people involved and 2 vehicles on scene. No outside assistance, only the people on the original scene are to be involved.
Bank Robbery/Vangelico/ - Maximum of 4 people involved and 2 vehicles on the scene. No outside assistance or additional getaway drivers outside of the limit of 4. Not all 4 people have to be on the scene of the initial robbery.
Union Depository/Pacific Standard Bank - Maximum of 8 people involved and 4 vehicles on the scene. No outside assistance or additional getaway drivers outside of the limit of 8. Not all 8 people have to be on the scene of the initial robbery.