Its not an unreasonable way of thinking, and it may very well be true as I don't think we've seen someone attempt to put Gai in a genjutsu while using the gates, but since its not something that's been confirmed in our RP its best to assume it doesn't work like that.
Okay and just to summarize, the three ways to break a genjutsu are:
1. Pain (Physical Energy Disruption)
2. Disrupting your Chakra Flow (Kai or similar techniques, Spiritual Energy Disruption)
3. Foreign Chakra
Oh, and also Medical Ninja are immune to genjutsu. If you want I can explain why, but I'm feeling a little lazy so only if you ask.
Now do you have any questions before we move on to techniques?