E-moli 36V /6Ah pack

Hi to all!
I want to build 36V /6Ah pack using Milwakee V18 packs. Each V18 is 3Ah.
I bought 4 of them and one charger.
My question is regarding BMS built into packs. How to use them, how to connect them.
I want to build 2S2P pack.
Pack is going to be used on TF bike so it must accept regen current damp on it at least 5A at the time.
Do you agree that BMS IS NOT able to accept any reverse current?
I understand Milwakee BMS DOES WHAT ALL BMS do - undervoltage, overdischarge, etc. protection.
From the thred I read on this forum I know that somebody connected 28V Milwakee unmodified in series means BMS inside in series.
BMS are between the load/drill/ and a battery. I am wondering , would BMS accept any reverse current. What about braking drill , when you release trigger it breaks like any cordless.
Or should I just use BMS only for charging and disconnect BMS during riding?
Any thoughts would be appreciated.
Thank you
MC