You are overthinking way too much. Do you seriously think that if you drink your intra-workout or BCAA in between routine 3 and 4 that it will make a difference (that you will notice of) compared to drinking it at routine 4-5 or 5-6 or 1-2 and so on? Just drink when you feel like so. Take a sip here and there. It does not matter. You need to sort out your priority first i.e. food intake before worrying about the timing of taking intra workout or bcaa.