It has been a year since I began the training, and after my mission in the pacific where one of my friend and colleague almost drowned I remembered how important this training was and then went in that lab everyday with more enthusiasm.
After all my lungs started to get very resilient and as I discovered what my body was capable of to survive I gained much more confidence, of course my chest was still hurtfull and sore but I learned to accept and ignore it to remain calm, which was good to begin the third phase : 7-10 minutes

Then at each session the first minutes were painfull and harsh until I start to get into my second state and relax for as long as I was asked to, actually my lungs got so ripped, trainned and efficient that I actually broke many of the agency's reccords, beating even prestigious agents who managed to hold for long periods of time thanks to their species advantages such as penguins, otters or crocodiles.
Actually, I was the very first small earthly mammal to reach ten minutes in the agency!
Now I am ready to start the final phase of my training...