All TRX are synchronized and they start their hopping sequence at the exact same time.
It’s not the arrival of one MS that will start the sequence.
In your example, the MS3 on TRX3 will use a frequency f10 at TDMA = i. This frequency f10 is going to be used by MS1 on TRX2 during TDMA = i + 2 (the MAIO difference between TRX 2 and TRX 3).
In other words, TRX 2 is always 2 frequencies behind TRX 3:
initialization of TRX:
TDMA = 0, TRX 2 = f2 (MAIO2), TRX3 = f4 (MAIO4)
TDMA = 1, TRX 2 = f3, TRX3 = f5
TDMA = 2, TRX 2 = f4, TRX3 = f6
TDMA = 3, TRX 2 = f5, TRX3 = f7
It’s always like this, whether or not there is a MS on a TRX or not. Even when a TRX is “idle”, the sequence continues (even though there are no frequencies emitted in the Air)